Polymer electrolytes(PEs)have been long recognized as the key materials to enable energy-dense batteries and render flexible energy devices practically viable,owing to their chemical and mechanical reliability.However...Polymer electrolytes(PEs)have been long recognized as the key materials to enable energy-dense batteries and render flexible energy devices practically viable,owing to their chemical and mechanical reliability.However,much of their promise is yet to be realized.The roomtemperature ion conductivity of existing PEs still falls short of the implementation criterion of 10^(-4) S cm^(-1) on the promise of acceptable mechanical properties,thereby precluding their practical application.The twin but inversely related duties of polymers,that is,functioning as both an ion-conducting medium and a structural backbone,underlie this issue but are less elucidated systematically.The polyacrylate(PA)family is among promising polymer matrices on account of ester polarity,electrode compatibility,chemical tunability,and mechanical durability.The extensive applicability of PA in plasticized gels,dry solids,and emerging composites makes PA-based PEs representative to illustrate the trade-off between ion conduction and mechanical strength.We herein seek to outline the stated long-standing conflict exemplified by PA-based PEs,focusing on crucial strategies toward balancing and reconciling the two mutually exclusive properties,with the intention of offering designing guidelines for next-generation PEs.展开更多
The interpenetrating polymer network(IPN) systems have attracted a lot of attention because of their unique two-phase structure and properties. There have been many publications concerning the IPNs in which poly (isop...The interpenetrating polymer network(IPN) systems have attracted a lot of attention because of their unique two-phase structure and properties. There have been many publications concerning the IPNs in which poly (isoprene) (PIP) or polyacrylates (PAC) is formed as one of the networks.In the present study, Four serles of natural rubber(NR)/PAC IPNs were prepared and their morphologies were investigated with dynamic mechanics analysis(DMA) and transmission electron microscopy (TEM).展开更多
A polyacrylate/polyurethane (P(A) / P(U)) composite coating has been prepared bycrosslinking an acetoacetylated polyacrylate with a vinylic group terminated polyurethaneat room temperature. A model Michael reaction be...A polyacrylate/polyurethane (P(A) / P(U)) composite coating has been prepared bycrosslinking an acetoacetylated polyacrylate with a vinylic group terminated polyurethaneat room temperature. A model Michael reaction between ethyl acetoacetate (EAA) andmethyl acrylate (MA) was designed to study the crosslinking mechanism. It was foundthat the two active hydrogen atoms in acetoacetyl group can both add to vinylic groupsand the yield of mono- and bis-adducts are much affected by the molar ratio of acetoacetylto vinylic groups. Higher crosslinking degree and better properties could be obtained withdecreasing the molar ratio of the two active groups from 1/1 to 0.6/1 in the compositecoatings.展开更多
Electrical conductivity of chromium polyacrylate with dopant concentration 30, 40 and 50 wt-% of chromium has been measured over a broad range of temperatures (303 K to 383 K).The electrical conductivity shows depende...Electrical conductivity of chromium polyacrylate with dopant concentration 30, 40 and 50 wt-% of chromium has been measured over a broad range of temperatures (303 K to 383 K).The electrical conductivity shows dependence on temperature, as well as, level of doping. The conductivity is considered to be due to thermal hopping motion of localized charge carriers,which are believed to be polarons, in the temperature range 303 K to 323 K and for T>343 K,whereas. it is metal-like in the temperature range 323 K to 343展开更多
Free radical polymerized palladium polyacrylate was characterized by X-ray diffraction. Various parameters including mean crystallite size, interchain separation and radius of gyration have been calculated and discuss...Free radical polymerized palladium polyacrylate was characterized by X-ray diffraction. Various parameters including mean crystallite size, interchain separation and radius of gyration have been calculated and discussed with respect to the concentration of Pd in the polymeric salt. The results show that polymer is predominantly amorphous in nature.展开更多
Water control is a major problem in crop production, particularly in fragile ecosystems such as the Sahel. Water is the most important factor in plant productivity. Many initiatives have been developed in this directi...Water control is a major problem in crop production, particularly in fragile ecosystems such as the Sahel. Water is the most important factor in plant productivity. Many initiatives have been developed in this direction, including all methods of irrigation and water and soil conservation. The objective of this work is to assess the effectiveness of this amendment in crop production in the context of climate variability. The methodology is based on experi<span>mentation to statistically compare the natural biomass on a soil of sil</span><span>ty-clay-sandy texture, divided into two blocks, one of which is amended with potassium polyacrylate and the other is not. This study showed that the wet and dry biomasses produced on soils with potassium polyacrylate are significantly higher than those produced on unamended soils at the 5% threshold. Based on these results, potassium polyacrylate may be a solution to recurrent dryness pockets. However, uncontrolled environmental testing is necessary to confirm these results.</span>展开更多
Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties ...Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties of moisture absorption, such as monomer concentration, dosage of initiator, and reaction temperature were systematically investigated. The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material, such as silica gel, and molecular sieve. The best reaction condition and formula are based on the orthogonal experiment design. The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g. The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis. The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency, followed by monomer concentration and reaction temperature, while other factors have less influence.展开更多
The flocculation effects of homemade hydroxamated flocculant(HPAA)and commercially available sodium polyacrylate(PAAS)on synthetic goethite suspensions with different solid contents were studied.The adsorption mechani...The flocculation effects of homemade hydroxamated flocculant(HPAA)and commercially available sodium polyacrylate(PAAS)on synthetic goethite suspensions with different solid contents were studied.The adsorption mechanism of HPAA or PAAS on the surfaces of goethite was investigated.The settling rate of 50 g/L goethite suspension with HPAA(1.74 m/h)was faster than that with PAAS(0.54 m/h),which indicated that HPAA exhibits better flocculation performance than PAAS does.It could be found that the stretching vibration of carbonyl band in hydroxamic acid groups of HPAA was downshifted from 1 654 cm^(-1) to 1 645 cm^(-1) and a new adsorption band appeared at 1 455 cm-1,which demonstrated that a five-membered ring chelate may be formed among iron atoms of goethite surfaces,the hydroxyl groups and the carbonyl groups in hydroxamic acid groups of HPAA.In the case of PAAS,the separation of the asymmetric and symmetric stretches of the carboxylate groups in adsorbed PAAS was 163 cm-1,which was greater than that of unadsorbed PAAS with 157 cm^(-1).There was no indication of a contribution from the monodentate adsorption between iron atoms of goethite surfaces and carboxylate groups of PAAS,but there may exist a bi-dentate bridging structure.Compared with synthetic goethite,XPS curve fittings of Fe 2p spectra showed that the binding energies of the main Fe 2p3/2 and Fe 2p1/2 resolved peaks on HPAA-treated goethite surfaces were correspondingly decreased by 0.9 and 0.7 e V,while those on PAAS-treated goethite surfaces were correspondingly decreased by 0.7 and 0.3 e V.The characteristic N 1s peak of HPAA and C 1s peak of PAAS were correspondingly detected on HPAA-treated and PAAS-treated goethites,and a binding energy change of N 1s spectrum of adsorbed HPAA was observed.The relative atomic ratios of C/Fe,N/Fe and O/Fe on HPAA-treated and PAAS-treated goethite surfaces were increased.All the results suggested that HPAA or PAAS was adsorbed on the goethite surfaces by the chemisorption,and a stronger adsorption of HPAA on the goethite surfaces happened than that of PAAS.展开更多
The presence of hydrogen bonding in chloroform and polyacrylate mixtures was demonstrated by observation of 1H and 13 C NMR chemical shifts. Comparison of the nuclear magnetic resonance (NMR) chemical shift in polymer...The presence of hydrogen bonding in chloroform and polyacrylate mixtures was demonstrated by observation of 1H and 13 C NMR chemical shifts. Comparison of the nuclear magnetic resonance (NMR) chemical shift in polymer solutions with their low molecular mass analogues showed the effect of steric hindrance on hydrogen bonding. This initial investigation is helpful for understanding the intermolecular interaction in relatively weak hydrogen bonding polymer solutions.展开更多
A series of“guava-like”silica/polyacrylate nanocomposite particles with close silica content and different grafting degrees were prepared via mini-emulsion polymerization using 3-(trimethoxysilyl)propyl methacrylate...A series of“guava-like”silica/polyacrylate nanocomposite particles with close silica content and different grafting degrees were prepared via mini-emulsion polymerization using 3-(trimethoxysilyl)propyl methacrylate(TSPM)modified silica/acrylate dispersion.The silica/polyacrylate composite particles were melt-mixed with unfilled polyacrylate(PA)resin to prepare corresponding silica/polyacrylate molded composites and the dispersion mechanism of these silica particles from the“guava-like”composite particles into polyacrylate matrix was studied.It was calculated that about 110 silica particles were accumulated in the bulk of every silica/polyacrylate composite latex particle.Both the solubility tests of silica/polyacrylate composite latex particles in tetrahydrofuran(THF)and the section transmission electron microscope(TEM)micrographs of silica/polyacrylate molded composites indicated that the grafting degree of silica particles played a crucial role in the dispersion of silica/polyacrylate composite particles into the polyacrylate matrix.When the grafting degree of polyacrylate onto silica was in a moderate range(ca.20%-70%),almost all of silica particles in these“guava-like”composite particles were dispersed into the polyacrylate matrix in a primaryparticle-level.However,at a lower grafting degree,massive silica aggregations were found in molded composites because of the lack of steric protection.At a greater grafting degree(i.e.,200%),a cross-linked network was formed in the silica/polyacrylate composite particles,which prevented the dispersion of composite particles in THF and polyacrylate matrix as primary particles.展开更多
The hybrid materials are widely used in various fields for excellent performance. However, there are few researches studying their failure process. In order to prepare the hybrid materials with better performance, the...The hybrid materials are widely used in various fields for excellent performance. However, there are few researches studying their failure process. In order to prepare the hybrid materials with better performance, the failure process needs to be well studied. Two kinds of silica/polyacrylate films are successfully prepared to study the effect of organic-inorganic interaction on performance. The average diameter of silica particles is measured to be around 342 nm by scanning electron microscope(SEM). Wear test demonstrates the hybrid film, which is obtained by grafting polyacrylate onto silica particles, possesses more excellent properties than the one filled directly with silica particles. The stronger interaction between organic and inorganic components leads to a better distribution of inorganic particles within the polymer matrix. In this work, a model is presented to illustrate the deterioration process of the hybrid films, which allows us to further understand the hybrid materials.展开更多
Despite aqueous electrolytes having a low cost and excellent ionic conductivity,their low withstand voltage of 1.2 V makes them problematic for battery utility because that is a very important factor in battery produc...Despite aqueous electrolytes having a low cost and excellent ionic conductivity,their low withstand voltage of 1.2 V makes them problematic for battery utility because that is a very important factor in battery production.In this research,the possibility of increasing the withstand voltage while maintaining the low cost of aqueous electrolytes was investigated.In this research,the solution electrolyte was made into a viscous solid polymer electrolyte to improve the withstand voltage of the electrolyte.A solid polymer electrolyte was made from sodium polyacrylate and doped with KOH(potassium hydroxide)and pure water.The improvement of the withstand voltage was evaluated by the specific capacitance.展开更多
The effectiveness of a superabsorbent polymer of sodium polyacrylate was studied, with emphasis on water management, i.e., absorption, retention and desorption in the soil. The polymer was applied in plots with a sand...The effectiveness of a superabsorbent polymer of sodium polyacrylate was studied, with emphasis on water management, i.e., absorption, retention and desorption in the soil. The polymer was applied in plots with a sandy soil near Grandola (southern Portugal). Characterization of the most relevant physical and chemical properties of the polymer was made, namely, its specific gravity, particle diameter, capacity of water absorption and desorption. In the plots with and without the polymer, soil moisture was continuously monitored, and grassland biomass samples were collected and weighed. The results reflected the effective role of the polymer both in the improvement of the water regime in the soil and in the substantial increment of grassland productivity.展开更多
Hydrogel is considered as an important material in our world nowadays as it is used in many important and significant applications such as in tissue engineering and agriculture. There are hundreds of types of such mat...Hydrogel is considered as an important material in our world nowadays as it is used in many important and significant applications such as in tissue engineering and agriculture. There are hundreds of types of such materials, where most of them can be easily prepared. The main objective of this work is to prepare one of the hydrogel types which could be very useful in the agriculture of deserts where plants in dry places require water in order to grow up. There are many places around the world where raining occurs only once or twice a year. There are also places where it does not rain at all. Therefore, hydrogels are required in order to absorb water in large quantities either during raining or irrigation instead of escaping to underground and then eject them to the roots of plants over time as the plants require watering. In this research a hydrogel based on acryl amide, Poly 2-Acrylamide-2-Methyl-1-Propane Sulphonic Acid, (PAMPS) was prepared by using different percentages of a suitable cross-linking agent, Methylene-bis-Acrylamide. The cross-linker content is very important factor affects the rate and amount of absorbed water. The highest amount of absorbed water at 25°C was observed by using 0.6% cross-linking agent based on monomer mass. The temperature of absorbed water and its pH value are also essential factors that affect the rate and the amount of absorbed water and were investigated in this work. The highest amount of absorbed water was recorded at pH = 12 and at 60°C. The amount and the rate of water absorbed by Sodium Polyacrylate Hydrogel were also investigated at 25°C. The agriculture applications of hydrogel based on Sodium Polyacrylate were examined using Fenugreek seeds implanting.展开更多
Several polyacrylate matrixes were prepared with monomers such as methyl methacrylate, KH-570, acrylic acid and butyl acrylate, and the electrochromic behavior of their soluble PAn composite coatings was also studied ...Several polyacrylate matrixes were prepared with monomers such as methyl methacrylate, KH-570, acrylic acid and butyl acrylate, and the electrochromic behavior of their soluble PAn composite coatings was also studied by electrochemical analysis and spectrophotometry. It shows that the constitution of the polymer matrixes have great effects on the electrochromic process and the color change of the composite coatings. When the matrix consists of acrylic acid unit, PAn of both interior and exterior composite possesses the same electrochemical reactivity, shorter responding time and wider color-changing range. But it is contrary when matrixes contain no acrylic acid. Furthermore, the composite containing acrylic acid units has still electrochemical reactivity in distilled water instead of LiCIO,-PC electrolyte.展开更多
Novel side-chain liquid-crystalline poly(meth)acrylates were synthesized using 1-(3-hydroxyl-propyl)-3-[(4'-cyano-p-terphenyloxycarbonyl)alkyl]-1,1,3,3-tetramethyldisiloxane as the key intermediate. The polymers u...Novel side-chain liquid-crystalline poly(meth)acrylates were synthesized using 1-(3-hydroxyl-propyl)-3-[(4'-cyano-p-terphenyloxycarbonyl)alkyl]-1,1,3,3-tetramethyldisiloxane as the key intermediate. The polymers used a disiloxanemoiety as decoupling spacer with cyano-p-terphenyl as mesogenic unit. The products were characterized by NMR, GPC,DSC and polarizing optical microscopy. All the polymers with cyano-p-terphenyl mesogens formed a stable mesophase.However, if the mesogenic unit is replaced by cyano-p-biphenyl, the liquid crystalline character will be lost. The results alsoshowed that the decoupling is incomplete even if a complex and very flexible decoupling spacer is deliberately incorporatedto obtain the highest possible decoupling effect.展开更多
Superabsorbents starch grafted sodium polyacrylate was synthesized by inverse suspension polymerization, using toluene as the continuous phase, potassium persulfate as the initiator. The effect of reaction parameters,...Superabsorbents starch grafted sodium polyacrylate was synthesized by inverse suspension polymerization, using toluene as the continuous phase, potassium persulfate as the initiator. The effect of reaction parameters, such as starch pretreatment temperature, neutralization degree of monomer, reaction time and temperature, concentration of initiator, molar ratio of monomer and starch, on water absorbency of the starch grafted polymer was studied. The effects of the last two parameters were investigated by uniform design method, and the prediction equation was obtained.展开更多
Superabsorbents starch grafted sodium polyacrylate was prepared by inverse suspension polymerization, using toluene as the continuous phase, potassiun persulfate as the initiator. The effect of suspension parameters, ...Superabsorbents starch grafted sodium polyacrylate was prepared by inverse suspension polymerization, using toluene as the continuous phase, potassiun persulfate as the initiator. The effect of suspension parameters, such as volume ratio of continuous phase and dispersed phase,type and dosage of suspending agents, on water absorbency of the starch grafted polymer was studied.Different starch derivatives were also investigated.Superabsorbents made of cationic starch has higher water absorbency than that made of native corn starch.展开更多
基金National Natural Science Foundation of China,Grant/Award Numbers:21975271,22139001Shandong Energy Institute,Grant/Award Number:SEI I202127+3 种基金Youth Innovation Promotion Association of CAS,Grant/Award Number:2019214Key Scientific and Technological Innovation Project of Shandong,Grant/Award Number:2020CXGC010401Major basic research projects of Shandong Natural Science Foundation,Grant/Award Number:ZR2020ZD07Strategic Priority Research Program of Chinese Academy of Sciences,Grant/Award Number:XDA22010600。
文摘Polymer electrolytes(PEs)have been long recognized as the key materials to enable energy-dense batteries and render flexible energy devices practically viable,owing to their chemical and mechanical reliability.However,much of their promise is yet to be realized.The roomtemperature ion conductivity of existing PEs still falls short of the implementation criterion of 10^(-4) S cm^(-1) on the promise of acceptable mechanical properties,thereby precluding their practical application.The twin but inversely related duties of polymers,that is,functioning as both an ion-conducting medium and a structural backbone,underlie this issue but are less elucidated systematically.The polyacrylate(PA)family is among promising polymer matrices on account of ester polarity,electrode compatibility,chemical tunability,and mechanical durability.The extensive applicability of PA in plasticized gels,dry solids,and emerging composites makes PA-based PEs representative to illustrate the trade-off between ion conduction and mechanical strength.We herein seek to outline the stated long-standing conflict exemplified by PA-based PEs,focusing on crucial strategies toward balancing and reconciling the two mutually exclusive properties,with the intention of offering designing guidelines for next-generation PEs.
文摘The interpenetrating polymer network(IPN) systems have attracted a lot of attention because of their unique two-phase structure and properties. There have been many publications concerning the IPNs in which poly (isoprene) (PIP) or polyacrylates (PAC) is formed as one of the networks.In the present study, Four serles of natural rubber(NR)/PAC IPNs were prepared and their morphologies were investigated with dynamic mechanics analysis(DMA) and transmission electron microscopy (TEM).
文摘A polyacrylate/polyurethane (P(A) / P(U)) composite coating has been prepared bycrosslinking an acetoacetylated polyacrylate with a vinylic group terminated polyurethaneat room temperature. A model Michael reaction between ethyl acetoacetate (EAA) andmethyl acrylate (MA) was designed to study the crosslinking mechanism. It was foundthat the two active hydrogen atoms in acetoacetyl group can both add to vinylic groupsand the yield of mono- and bis-adducts are much affected by the molar ratio of acetoacetylto vinylic groups. Higher crosslinking degree and better properties could be obtained withdecreasing the molar ratio of the two active groups from 1/1 to 0.6/1 in the compositecoatings.
文摘Electrical conductivity of chromium polyacrylate with dopant concentration 30, 40 and 50 wt-% of chromium has been measured over a broad range of temperatures (303 K to 383 K).The electrical conductivity shows dependence on temperature, as well as, level of doping. The conductivity is considered to be due to thermal hopping motion of localized charge carriers,which are believed to be polarons, in the temperature range 303 K to 323 K and for T>343 K,whereas. it is metal-like in the temperature range 323 K to 343
文摘Free radical polymerized palladium polyacrylate was characterized by X-ray diffraction. Various parameters including mean crystallite size, interchain separation and radius of gyration have been calculated and discussed with respect to the concentration of Pd in the polymeric salt. The results show that polymer is predominantly amorphous in nature.
文摘Water control is a major problem in crop production, particularly in fragile ecosystems such as the Sahel. Water is the most important factor in plant productivity. Many initiatives have been developed in this direction, including all methods of irrigation and water and soil conservation. The objective of this work is to assess the effectiveness of this amendment in crop production in the context of climate variability. The methodology is based on experi<span>mentation to statistically compare the natural biomass on a soil of sil</span><span>ty-clay-sandy texture, divided into two blocks, one of which is amended with potassium polyacrylate and the other is not. This study showed that the wet and dry biomasses produced on soils with potassium polyacrylate are significantly higher than those produced on unamended soils at the 5% threshold. Based on these results, potassium polyacrylate may be a solution to recurrent dryness pockets. However, uncontrolled environmental testing is necessary to confirm these results.</span>
基金Supported by the 863 Project (Grant No. 2005AA001650)
文摘Sodium polyacrylate was synthesized with acrylic acid as the monomer, and sodium bisulfate and ammonium persulfate as the initiator, by means of aqueous solution polymerization. The factors influencing the properties of moisture absorption, such as monomer concentration, dosage of initiator, and reaction temperature were systematically investigated. The experimental results indicate that the moisture-absorbing property of this polymer was better than other traditional material, such as silica gel, and molecular sieve. The best reaction condition and formula are based on the orthogonal experiment design. The optimum moisture absorbency of sodium polyacrylate reaches 1.01 g/g. The mathematical correlation of this polymer with various factors and moisture absorbency is obtained based on the multiple regression analysis. The moisture content intuitive analysis table shows that neutralization degree has the most significant influence on moisture absorbency, followed by monomer concentration and reaction temperature, while other factors have less influence.
基金Supported by the National Natural Science Foundation of China(No.5117423151134007)
文摘The flocculation effects of homemade hydroxamated flocculant(HPAA)and commercially available sodium polyacrylate(PAAS)on synthetic goethite suspensions with different solid contents were studied.The adsorption mechanism of HPAA or PAAS on the surfaces of goethite was investigated.The settling rate of 50 g/L goethite suspension with HPAA(1.74 m/h)was faster than that with PAAS(0.54 m/h),which indicated that HPAA exhibits better flocculation performance than PAAS does.It could be found that the stretching vibration of carbonyl band in hydroxamic acid groups of HPAA was downshifted from 1 654 cm^(-1) to 1 645 cm^(-1) and a new adsorption band appeared at 1 455 cm-1,which demonstrated that a five-membered ring chelate may be formed among iron atoms of goethite surfaces,the hydroxyl groups and the carbonyl groups in hydroxamic acid groups of HPAA.In the case of PAAS,the separation of the asymmetric and symmetric stretches of the carboxylate groups in adsorbed PAAS was 163 cm-1,which was greater than that of unadsorbed PAAS with 157 cm^(-1).There was no indication of a contribution from the monodentate adsorption between iron atoms of goethite surfaces and carboxylate groups of PAAS,but there may exist a bi-dentate bridging structure.Compared with synthetic goethite,XPS curve fittings of Fe 2p spectra showed that the binding energies of the main Fe 2p3/2 and Fe 2p1/2 resolved peaks on HPAA-treated goethite surfaces were correspondingly decreased by 0.9 and 0.7 e V,while those on PAAS-treated goethite surfaces were correspondingly decreased by 0.7 and 0.3 e V.The characteristic N 1s peak of HPAA and C 1s peak of PAAS were correspondingly detected on HPAA-treated and PAAS-treated goethites,and a binding energy change of N 1s spectrum of adsorbed HPAA was observed.The relative atomic ratios of C/Fe,N/Fe and O/Fe on HPAA-treated and PAAS-treated goethite surfaces were increased.All the results suggested that HPAA or PAAS was adsorbed on the goethite surfaces by the chemisorption,and a stronger adsorption of HPAA on the goethite surfaces happened than that of PAAS.
基金the Foundation for Basic Research ofTsinghua U niversity(No.JC2 0 0 0 0 4 1)
文摘The presence of hydrogen bonding in chloroform and polyacrylate mixtures was demonstrated by observation of 1H and 13 C NMR chemical shifts. Comparison of the nuclear magnetic resonance (NMR) chemical shift in polymer solutions with their low molecular mass analogues showed the effect of steric hindrance on hydrogen bonding. This initial investigation is helpful for understanding the intermolecular interaction in relatively weak hydrogen bonding polymer solutions.
文摘A series of“guava-like”silica/polyacrylate nanocomposite particles with close silica content and different grafting degrees were prepared via mini-emulsion polymerization using 3-(trimethoxysilyl)propyl methacrylate(TSPM)modified silica/acrylate dispersion.The silica/polyacrylate composite particles were melt-mixed with unfilled polyacrylate(PA)resin to prepare corresponding silica/polyacrylate molded composites and the dispersion mechanism of these silica particles from the“guava-like”composite particles into polyacrylate matrix was studied.It was calculated that about 110 silica particles were accumulated in the bulk of every silica/polyacrylate composite latex particle.Both the solubility tests of silica/polyacrylate composite latex particles in tetrahydrofuran(THF)and the section transmission electron microscope(TEM)micrographs of silica/polyacrylate molded composites indicated that the grafting degree of silica particles played a crucial role in the dispersion of silica/polyacrylate composite particles into the polyacrylate matrix.When the grafting degree of polyacrylate onto silica was in a moderate range(ca.20%-70%),almost all of silica particles in these“guava-like”composite particles were dispersed into the polyacrylate matrix in a primaryparticle-level.However,at a lower grafting degree,massive silica aggregations were found in molded composites because of the lack of steric protection.At a greater grafting degree(i.e.,200%),a cross-linked network was formed in the silica/polyacrylate composite particles,which prevented the dispersion of composite particles in THF and polyacrylate matrix as primary particles.
基金Supported by the Southwest Petroleum University Outstanding Researcher Grant(201331010015)
文摘The hybrid materials are widely used in various fields for excellent performance. However, there are few researches studying their failure process. In order to prepare the hybrid materials with better performance, the failure process needs to be well studied. Two kinds of silica/polyacrylate films are successfully prepared to study the effect of organic-inorganic interaction on performance. The average diameter of silica particles is measured to be around 342 nm by scanning electron microscope(SEM). Wear test demonstrates the hybrid film, which is obtained by grafting polyacrylate onto silica particles, possesses more excellent properties than the one filled directly with silica particles. The stronger interaction between organic and inorganic components leads to a better distribution of inorganic particles within the polymer matrix. In this work, a model is presented to illustrate the deterioration process of the hybrid films, which allows us to further understand the hybrid materials.
文摘Despite aqueous electrolytes having a low cost and excellent ionic conductivity,their low withstand voltage of 1.2 V makes them problematic for battery utility because that is a very important factor in battery production.In this research,the possibility of increasing the withstand voltage while maintaining the low cost of aqueous electrolytes was investigated.In this research,the solution electrolyte was made into a viscous solid polymer electrolyte to improve the withstand voltage of the electrolyte.A solid polymer electrolyte was made from sodium polyacrylate and doped with KOH(potassium hydroxide)and pure water.The improvement of the withstand voltage was evaluated by the specific capacitance.
文摘The effectiveness of a superabsorbent polymer of sodium polyacrylate was studied, with emphasis on water management, i.e., absorption, retention and desorption in the soil. The polymer was applied in plots with a sandy soil near Grandola (southern Portugal). Characterization of the most relevant physical and chemical properties of the polymer was made, namely, its specific gravity, particle diameter, capacity of water absorption and desorption. In the plots with and without the polymer, soil moisture was continuously monitored, and grassland biomass samples were collected and weighed. The results reflected the effective role of the polymer both in the improvement of the water regime in the soil and in the substantial increment of grassland productivity.
文摘Hydrogel is considered as an important material in our world nowadays as it is used in many important and significant applications such as in tissue engineering and agriculture. There are hundreds of types of such materials, where most of them can be easily prepared. The main objective of this work is to prepare one of the hydrogel types which could be very useful in the agriculture of deserts where plants in dry places require water in order to grow up. There are many places around the world where raining occurs only once or twice a year. There are also places where it does not rain at all. Therefore, hydrogels are required in order to absorb water in large quantities either during raining or irrigation instead of escaping to underground and then eject them to the roots of plants over time as the plants require watering. In this research a hydrogel based on acryl amide, Poly 2-Acrylamide-2-Methyl-1-Propane Sulphonic Acid, (PAMPS) was prepared by using different percentages of a suitable cross-linking agent, Methylene-bis-Acrylamide. The cross-linker content is very important factor affects the rate and amount of absorbed water. The highest amount of absorbed water at 25°C was observed by using 0.6% cross-linking agent based on monomer mass. The temperature of absorbed water and its pH value are also essential factors that affect the rate and the amount of absorbed water and were investigated in this work. The highest amount of absorbed water was recorded at pH = 12 and at 60°C. The amount and the rate of water absorbed by Sodium Polyacrylate Hydrogel were also investigated at 25°C. The agriculture applications of hydrogel based on Sodium Polyacrylate were examined using Fenugreek seeds implanting.
基金Funded by National "863" Project(No. 863-715-014-0100).
文摘Several polyacrylate matrixes were prepared with monomers such as methyl methacrylate, KH-570, acrylic acid and butyl acrylate, and the electrochromic behavior of their soluble PAn composite coatings was also studied by electrochemical analysis and spectrophotometry. It shows that the constitution of the polymer matrixes have great effects on the electrochromic process and the color change of the composite coatings. When the matrix consists of acrylic acid unit, PAn of both interior and exterior composite possesses the same electrochemical reactivity, shorter responding time and wider color-changing range. But it is contrary when matrixes contain no acrylic acid. Furthermore, the composite containing acrylic acid units has still electrochemical reactivity in distilled water instead of LiCIO,-PC electrolyte.
基金This work was supported by NNSFC (No. 59873001).
文摘Novel side-chain liquid-crystalline poly(meth)acrylates were synthesized using 1-(3-hydroxyl-propyl)-3-[(4'-cyano-p-terphenyloxycarbonyl)alkyl]-1,1,3,3-tetramethyldisiloxane as the key intermediate. The polymers used a disiloxanemoiety as decoupling spacer with cyano-p-terphenyl as mesogenic unit. The products were characterized by NMR, GPC,DSC and polarizing optical microscopy. All the polymers with cyano-p-terphenyl mesogens formed a stable mesophase.However, if the mesogenic unit is replaced by cyano-p-biphenyl, the liquid crystalline character will be lost. The results alsoshowed that the decoupling is incomplete even if a complex and very flexible decoupling spacer is deliberately incorporatedto obtain the highest possible decoupling effect.
文摘Superabsorbents starch grafted sodium polyacrylate was synthesized by inverse suspension polymerization, using toluene as the continuous phase, potassium persulfate as the initiator. The effect of reaction parameters, such as starch pretreatment temperature, neutralization degree of monomer, reaction time and temperature, concentration of initiator, molar ratio of monomer and starch, on water absorbency of the starch grafted polymer was studied. The effects of the last two parameters were investigated by uniform design method, and the prediction equation was obtained.
文摘Superabsorbents starch grafted sodium polyacrylate was prepared by inverse suspension polymerization, using toluene as the continuous phase, potassiun persulfate as the initiator. The effect of suspension parameters, such as volume ratio of continuous phase and dispersed phase,type and dosage of suspending agents, on water absorbency of the starch grafted polymer was studied.Different starch derivatives were also investigated.Superabsorbents made of cationic starch has higher water absorbency than that made of native corn starch.