QSPR Study on the Glass Transition Temperature of Polyacrylates

Structural parameters of 22 polyacrylic compounds were computed at two levels using Hartree-Fock and DFT methods. Based on the experimental data of glass transition temperature （Tg）, four-parameter （energy of the lowest unoccupied molecular orbital （ELoMO）, the highest positive charge （Qmax^＋）, dipole moments（μ） and the next highest occupied molecular orbital （ENLOMO）） dependent equations were developed using structural parameters as theoretical descriptors. Especially, Tg dependent equation calculated at the HF/6-31G（d） level is more advantageous than others in view of their correlation and predictive abilities. This dependent equation was validated by variance inflation factors （VIF） and t-test methods.

Evidence of Hydrogen Bonding in Chloroform and Polyacrylates from NMR Measurements

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.

Trade-offs between ion-conducting and mechanical properties: The case of polyacrylate electrolytes

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.

Electrical Characteristics of Super Capacitors Using KOH Gel

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.

SYNTHESIS OF NOVEL LIQUID CRYSTALLINE POLY(METH)ACRYLATES CONTAINING SILOXANE SPACER AND TERPHENYLENE MESOGENIC UNIT

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 disiloxane moiety 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 also showed that the decoupling is incomplete even if a complex and very flexible decoupling spacer is deliberately incorporated to obtain the highest possible decoupling effect.

伏羲文化──中国传统文化之源

伏羲指上古畜牧业时融合许多部落文化的一个时代．伏羲文化指涵盖伏羲时代精神及物化的精神为主要内容、由后世不断丰富、对后世产生深远影响的远古文化，对中国传统哲学、婚姻家庭形态、生产力的发展、华夏民族的融合都产生了极大影响，成为中国传统文化的源泉．本文从伏羲文化的价值及其对中国传统文化的影响两个方面探讨了以上问题．

Synthesis of a Macromer, MPEGAA, Used to Prepare an AMPS-modified Polyacrylic Acid Superplasticizer

A macromer, methoxypolyethylene glycol acrylate （MPEGAA）, was synthesized by direct esterification using methoxypolyethylene glycol （MPEG-1200） and acrylic acid （AA） as the main materials. MPEGAA was then used to prepare a polyacrylic acid superplasticizer modified with 2-acrylamido-2- methylpropane sulfonic acid （AMPS）. A single-factor test was performed to investigate the effects of the molar ratio of acid to alcohol （n（AA）/n（MPEG））, inhibitor amount, catalyst amount, temperature, and time of esterification on the synthesis of MPEGAA. The experimental results showed that the optimal esterification conditions were as follows： n（AA）/n（MPEG）, 3.5：1; amount of hydroquinone （as an inhibitor）, 1.2%; amount of para-toluenesulfonic acid （as a catalyst）, 5.5%; reaction temperature, 95 ~C; and reaction time, 6 h. The AMPS- modified polyacrylic acid superplasticizer prepared under the optimal esterification conditions enabled the achievement and maintenance of high cement dispersibility. At an admixture amount of 0.15%, the cement paste fluidity was initially as high as 300 mm, and then decreased to 315 mm after 1 h and to 290 mm after 2 h.

Synthesis and Properties of an AMPS-Modified Polyacrylic Acid Superplasticizer

A 2-acrylamide-2-methyl propylene sodium sulfonic （AMPS）-modified polyacrylic acid superplasticizer was synthesized using aqueous solution polymerization with the major monomers including the self-made active macromers polyethylene glycol mono-methyl ether acrylate acrylic （MPEGAA）, acrylic acid （AA）, AMPS, and sodium methyl allyl sulfonate （SMAS）. The ratios of the monomers were determined using an orthogonal experiment. This research focused on the effects of the dosages of different macromers, the polymerization conditions, and the length of MPEGAA side chains on the properties of the AMPS-modified polyacrylic acid super-plasticizer. The best polymerization conditions of the AMPS-modified polyacrylic acid superplasticizer are when （n（MPEGAA）：n（SMAS）：n（AMPS）：n（AA） equals 0.1：0.1：0.2：0.65, the molecular weight of monomethoxypolyethylene glycol is 1 200, the initiator ammonium persulfate accounts for 5% of the total mass of the polymerized monomers, the polymerization temperature is 80 ~C, and the reaction time is 4 h. The AMPS-modified polyacrylic acid superplasticizer synthesized in the best conditions exhibited excellent dispersivity and dispersion retainability. When the dosage ratio was 0.24%, the initial fluidity was 400 mm and the fluidity had nearly no loss after 1 h.

The Synthesis Technique of Polyacrylic Acid Superplasticizer

Using water separation technique,acrylic acid （AA） and polyethylene glycol （PEG） 1000,of which the ratio was 1.5,were esterified and the optimum esterification ratio of 90% could be reached under the condition of 110 ℃×3 h.Using polyoxyethylene acrylate macromonomer （PA） prepared in the esterification,AA and sodium methylacryl sulfonate （MAS） as monomers,a copolymer which could be used as superplasticizer was prepared by free radical coolymerization in n（PA）：n（AA）：n（MAS） of 1：7：3.When the synthesis condition was 80 ℃× 5 h,the optimal dosage of initiator was 3.0%-4.0%,the fluidity of cement paste with the samples could reach 270 mm.By analyzing the effect of the content of residual small molecule sulfonic monomer on the properties of sample,n（MAS）/n（PA） was controlled in a range of 2.5-3.8.

Effects of an AMPS-Modified Polyacrylic Acid Superplasticizer on the Performance of Cement-based Materials

A self-made AMPS-modified polyacrylic acid superplasticizer and two others of the same type but with different molecular structures, which are commercially available, are used in this study to investigate the effect of a 2-acrylamide-2-methyl propylene sulfonic （AMPS）-modified polyacrylic acid superplasticizer on the properties of cement-based materials. In the experiments, initial fluidity, 1 and 2 h fluidity over time after admixtion, bleeding rate of the net cement mortar, and adsorption capacity and rate of cement particles are determined by adding different dosages of the three superplasticizers into the cement paste to characterize the dispersivity and the dispersion retention capability of each superplasticizer. Water-reducing rates of three kinds of mortars are simultaneously determined to characterize the water-reducing capacity of each superplasticizer, as well as the 3 and 28 d compressive strengths to characterize the compression resistance. Results show that water-reducing effect and fluidity better maintain the capability of the AMPS-modified polyacrylic acid superplasticizer than the two commercially available polyacrylic acid superplasticizers, and the compressive strengths after 3 and 28 d show significant growth. In conclusion, the effects of water reduction and strengthening of the AMPS-modified polyacrylic acid superplasticizer are evidently better than those of the two commercially available polyacrylic acid superplasticizers.

Influence of Carboxyl Groups on the Particle Size and Rheological Properties of Polyacrylate Latices

The PAL was synthesized with BA,MMA and some monomers containing carboxyl groups（for example,acrylic acid（AA） and methacrylic acid（MAA）） as co-monomers by semi-continuous seeded emulsion polymerization technique.The influences of alkalinization temperature,the feeding manner of AA or MAA on the particles size,rheological properties and carboxyl distribution of the latex were discussed,and the rheological mechanism was analyzed.The experimental results show that the PAL system has preferable viscosity and particle size when the alkalinization temperature is 50 ℃.Different distribution of carboxyl group in the particles and different resultant rheological properties are obtained by different feeding manner of AA or MAA into the system.The TEM images show that the particle is a smooth globe with carboxyl group concentrating on the surface and stabilized with electric double layer and nonionic adsorbed layer.The concentration of carboxyl functional group on the surface of particles can be achieved by the specific polymerization technique.The rheologyical properties are determined by accretion of particle volume and variation of the two phase volume ratio resulted from the carboxyl group spreading layer.

STUDIES ON THE BLEND OF POLYACRYLATE EMULSIONS AND TACKIFIER RESIN EMULSIONS

A series of polyacrylate emulsions were blended with tackifier resin emulsions such as modified rosin emulsion, C5 resin and C9 resin emulsion. The miscibility of the polyacrylates and tackifier resins was investigated by means of SEM and visual observation. The phase diagrams of the miscibility change systematically with the polarity of polyacrylates and tackifier resins. The influence of the content of the tackifier resins on the adhesion properties of the; polyacrylate emulsions were also studied. The results show that the 180 degrees C peel strength is improved as the amount of the tackifier resin increases and comes to a maximum at a specific content. The ball tack property decreases slightly and the hold strength changes complicatedly as the tackifier resin increases.

Studies on the Morphology of Natural Rubber/Polyacrylate Interpenetrating Polymer Networks

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).

Effect of Molecular Structure on the Performance of Polyacrylic Acid Superplasticizer

The effects of structure parameters, such as molecular structure, segment kinds, molecular weight, and organic functional groups, on the performance of polyacrylic acid superplasticizer were discussed. According to the differences of chain sections, functional groups, eic, polyacrylic acid superplasticizer could be divided into A, B, C three parts. Among them, A chain section included sulfonic acid groups, B chain section carboxyl groups, C chain section polyester. Polyacrylic acid superplasticizers with different matching of A, B, C chain sections, different length of C chain section and different molecular weights were synthesized by acrylic acid, polyethylene glycol, sodium methyl allylsulfonate; the relation between the molecular structure and perfolxnance was also studied. The expetimental results indicate that the water-reduction ratio increases obviously with the increment of the proportion of sodium methyl allylsulfonate chain section in the molecular; the slump retention increases greatly with the increment of the proportion of acrylic acid chain section; the dispersion of cement particles increases with the increment of the chain length of polyethylene glycol; when the molecular weight is in the range of 5000, the dispersion and slump retentibity increase with the increment of the average molecular weight of polymers.

Properties of Polyacrylate Latex Prepared Under Different Emulsified Systems

The polyacrylate latexes were synthesized via pre-emulsified and semi-continuous seeded emulsion polymerization technology when conventional surfactant or polymerizable surfactant was used as emulsifiers. The resultant latexes and their films were characterized with the contact angle determinator and rheometer. Effect of the polymerizable surfactant on water resistance, stability and rheology of the latex was studied. Results show that the water resistance of film is increased first then decreased with the increase of the amount of the polymerizable surfactant. There exists the optimum value of the amount of the polymerizable surfactant for the water resistance of the film. In comparison with the latex prepared with the conventional surfactant, both the mechanical stability and the freezing-thaw stability of the latex are improved when the polymerizable surfactant is used during the course of the emulsion polymerization. The resultant latex has rheological properties of pseudo-plastic fluid and belongs to non-Newtonian fluid.

SYNTHESIS, CROSSLINKING MECHANISM AND PROPERTIES OF A POLYACRYLATE/POLYURETHANE COMPOSITE COATING

A polyacrylate/polyurethane (P(A)/P(U)) composite coating has been prepared by crosslinking an acetoacetylated polyacrylate with a vinylic group terminated polyurethane at room temperature. A model Michael reaction between ethyl acetoacetate (EAA) and methyl acrylate (MA) was designed to study the crosslinking mechanism. It was found that the two active hydrogen atoms in acetoacetyl group can both add to vinylic groups and the yield of mono-and bis-adducts are much affected by the molar ratio of acetoacetyl to vinylic groups. Higher crosslinking degree and better properties could be obtained with decreasing the molar ratio of the two active groups from 1/1 to 0.6/1 in the composite coatings.

Determination of Ni^(2+) in Waters with Sodium Polyacrylate as a Binding Phase in Diffusive Gradients in Thin-films

An aqueous solution containing sodium polyacrylate（PAAS） was used in diffusive gradient in thin-films technique（DGT） to measure DGT-labile Ni2＋ concentrations.The DGT devices（PAAS DGT） were validated in four types of solutions,including synthetic river water containing metal ions with complexing EDTA or that without complexing EDTA,natural river water（Ling River,Jinzhou,China） spiked with Ni2＋,and an industrial wastewater （Jinzhou,China）.Results show that only free metal ions were measured by PAAS DGT,recovery=97.36% in the solutions containing only free metal ions,recovery=49.62% in a solution with metal/EDTA molar ratio of 2：1 and recovery=0 in the solutions with metal/EDTA molar ratios of 1：1 and 1：2.These indicated that the complexes of Ni-EDTA were DGT-inert.The DGT performance in spiked river water（recovery=18.24%） and in industrial wastewater（recovery=12.25%） were investigated,which indicated that the measurement of metals by this DGT device did not include the humic substances complexed fractions of metals.The binding properties of PAAS DGT for Ni2＋ were investigated under different conditions of pH value and ionic strength.Conditional stability constants（lgK） of PAAS-Ni complexes were also evaluated.

Investigation on the Use of the Weakly Basic Polyacrylate Anion-Exchanger Amberlite IRA-68 for Sorption and Separation of Iminodiacetate Complexes of Rare Earth Elements

Based on the determined affinity series of rare earth element complexes with IMDA for the anion-exchangers, purification of macroquantities of Nd 3+ from Y 3+, Sm 3+ from Ho 3+, La 3+ from Nd 3+ and La 3+ from Pr 3+ on the weakly basic gel anion-exchanger Amberlite IRA-68 was studied. Using the presented method on 1 L of Amberlite IRA-68 in the acetate form, it is possible to obtain about 240 g Nd 2O 3 purified from Y 2O 3. Great difference in affinity of La 3+ and Nd 3+ as well as Pr 3+ complexes for this anion-exchanger in the acetate form indicates the possibility of applying this process for purification of lanthanum on the increased scale. On 1 L of Amberilte IRA-68 in the acetate form it is possible to obtain about 1125 g La 2O 3 purified from Nd 2O 3. On the basis of these results it can be assumed that unique properties of polyacrylate anion-exchangers enable their application for separation of rare earth elements.

A new approach for development of vaccine against visceral leishmaniasis: Lipophosphoglycan and polyacrylic acid conjugates

Objective: To determine the antileishmanial vaccine effectiveness of lipophosphoglycan(LPG) and polyacrylic acids(PAA) conjugates on in vivo mice models.Methods: LPG molecule was isolated and purified from large-scale Leishmania donovani parasite culture. Protection efficacies of LPG alone, in combination with Freund's adjuvant, in a physical mixture and in conjugate(consisting of various LPG concentrations) with PAA, were comparatively determined by various techniques, such as cultivation with the micro-culture method, assessment of in vitro infection rates of peritoneal macrophages, determination of parasite load in liver with Leishman-Donovan Units, and detection of cytokine responses.Results: Obtained results demonstrated that the highest vaccine-mediated immune protection was provided by LPG-PAA conjugate due to all parameters investigated. According to the Leishman-Donovan Units results, the sharpest decline in parasite load was seen with a ratio of 81.17% when 35 mg LPG containing conjugate was applied. This value was 44.93% for the control group immunized only with LPG. Moreover, decreases in parasite load were 53.37%, 55.2% and 65.8% for the groups immunized with 10 mg LPG containing LPG-PAA conjugate, a physical mixture of the LPG–PAA, and a mixture of LPG + Freund's adjuvant, respectively. Furthermore, cytokine results supported that Th1 mediated protection occurred when mice were immunized with LPG-PAA conjugate.Conclusions: It has been demonstrated in this study that conjugate of LPG and PAA has an antileishmanial vaccine effect against visceral leishmaniasis. In this respect, the present study may lead to new vaccine approaches based on high immunogenic LPG molecule and adjuvant polymers in fighting against Leishmania infection.

Superabsorbent polymer for water management in forestry

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.