Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,p...Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.展开更多
One of the ways of overcoming the cost of irrigation is through in-situ water harvesting at the plant roots. Super absorbent polymer (SAP) can facilitate water harvesting at the plant roots. This study attempted to as...One of the ways of overcoming the cost of irrigation is through in-situ water harvesting at the plant roots. Super absorbent polymer (SAP) can facilitate water harvesting at the plant roots. This study attempted to assess the effect of SAP on plant available water (PAW) of different soils. In this study, SAP was sequentially added at the rate of 0.2%, 0.3% and 0.5% of the soil weight and its impact assessed in clay, sandy clay and sandy loam soils. The moisture retention characteristics of the original and SAP treated soils were studied using soil water retention curves (SWRC) and results modelled using Gardner model. PAW was estimated from SWRC as the difference between moisture content at 1.5 and 3 bar in all soils. The difference in PAW between original and treated soils was assessed at 5% level of significance. The WRC of all the samples was adequately found to be described by the Gardner model (Coefficient of determination R<sup>2</sup> ≥ 98% and residual standard error (RSE) ≤ 0.04). SWRC changed with increase in SAP percentage in clay, sandy clay and sandy loam soils. Clay had a higher change in water retention then sandy clay and lastly sandy loam. Plant available water content (PAW) in all soils increased. In clay soil it increased with increase in SAP from 0.3291 at zero SAP to 0.6223 at 0.5% SAP. Sandy clay soil increased in PAW from 0.2721 at zero SAP to 0.5335 at 0.5% SAP and Sandy loam soils from 0.1691 at zero SAP to 0.3461 at 0.5% SAP. Hence, from the study SAP can be used to conserve irrigation water in the plant roots and therefore reducing the cost since PAW has been increased.展开更多
The effects of super absorbent polymers （SAP） on yield as well as water-saving and drought-escaping mechanism in spring maize in the seasonal drought region were studied. As shown by the results, during the seasonal...The effects of super absorbent polymers （SAP） on yield as well as water-saving and drought-escaping mechanism in spring maize in the seasonal drought region were studied. As shown by the results, during the seasonal drought in southern China, SAP treatment promoted the soil moisture, improved the capability of absorption and transportation of roots, promoted physiological and biochemical functions, increased the chlorophyll content, photosynthetic rate and intercellular CO2 concentration, and reduced the stomatal conductance and transplre.tion rate. As a result, the economic characters of spring maize were improved, and the yield was increased.展开更多
The effect of super absorbent polymer（SAP） on the formation of tetrahydrofuran（THF） hydrate was studied by the successional cooling method.It was found that THF solution samples with 0.004 wt% and 0.03 wt% of SAP ...The effect of super absorbent polymer（SAP） on the formation of tetrahydrofuran（THF） hydrate was studied by the successional cooling method.It was found that THF solution samples with 0.004 wt% and 0.03 wt% of SAP formed THF hydrate completely during the same cooling process.The corresponding induction time was 16-29 min,14-31 min,respectively,which was obviously shorter than that of THF solution samples without SAP（25-62 min）.It indicated that SAP accelerated the formation of THF hydrate.At the same time,the pictures of hydrate formation with and without SAP had been compared.It was found that SAP did not change the morphology of the hydrate.Finally,the mechanism of SAP promoting effect on the formation of THF hydrate was suggested.展开更多
The grafting polyacrylamide onto wood pulp cellulose (cell g PAM) was performed with cerous ammonium nitrate as the initiator and hydrolyzed to produce the super absorbent resin. The FTIR shows that the polyacrylami...The grafting polyacrylamide onto wood pulp cellulose (cell g PAM) was performed with cerous ammonium nitrate as the initiator and hydrolyzed to produce the super absorbent resin. The FTIR shows that the polyacrylamide is grafted on the cellulose. After hydrolyzation, part of acrylamino groups are transformed into carboxyl groups. The XRD analysis shows that the graft polymerization occurred at the amorphous section and the surface of the crystal section of cellulose. The SEM graph reveals that there is a layer of polymer on the surface of cellulose fiber and the fibril structure of the cellulose surface is covered. After hydrolyzation, the surface of the product is different from that of cell g PAM's and the surface is scraggy. The technical conditions to prepare high water absorbent resin were confirmed. Through the radical graft copolymerization, the high water absorbent resin can be produced from wood pulp cellulose.展开更多
A super absorbent material was prepared with the super absorbent resin （ SAR ） and inorganic gel. The SAR of the carboxymethyl cellulose grafting acrylic acid （ CMC-AA ） was copolymer synthesized using the method ...A super absorbent material was prepared with the super absorbent resin （ SAR ） and inorganic gel. The SAR of the carboxymethyl cellulose grafting acrylic acid （ CMC-AA ） was copolymer synthesized using the method of inverse-phase suspension polymerization. The influences of the monomer concentration, neutralization degree, the initiator, dispersion agent, cross-linking agent, reaction and drying temperature on the grafting copolymer properties were examined. Meanwhlie, its properties was investigated and the model for absorption mechanism of this absorbent composite was proposed.展开更多
The two kinds of super absorbent resins from carboxymethyl cellulose were synthesized with the potassium persulphate and methylenebisacrylamide as initiator and cross linker respectively by radical polymerization in a...The two kinds of super absorbent resins from carboxymethyl cellulose were synthesized with the potassium persulphate and methylenebisacrylamide as initiator and cross linker respectively by radical polymerization in aqueous solution. Thestructures of the two resins were characterized with Fourier transform infrared spectroscopy FTIR, scanning electron miscroscopy （SEM）, and environment scanning electron miscroscopy （ESEM）, the results indicate that the fibriform of the carboxymethyl cellulose （CMC） is disappeared and the crusslink networks in eopolymer of carboxymethyl cellulose-graft-polyacrylic acid（CMC-g-PAA） are denser than that of eopolymer of carboxymethyl cellulose-graft-poly （acrylic acid-co-N-vinyl Pyrrolidone） （CMC-g- PAA-co-PVP）. The comparison between the two resins in absorption capacities is that CMC-g-PAA is better in the water-keep capability being heated, while CMC-g-PAA-co-PVP is better in the water absorbency and salt resistance.展开更多
Due to large volume and high hardness of thermal insulation materials mostly used in high temperature fields, a composite cooling powder and its thixotropic hydrogel for thermal protection are presented. The core of c...Due to large volume and high hardness of thermal insulation materials mostly used in high temperature fields, a composite cooling powder and its thixotropic hydrogel for thermal protection are presented. The core of composite cooling material powder is super absorbent polymer, composing with metal salt, polysaccharide hydrosol and inorganic particles and other modifiers through a series of composite process, which can be easily stored for a long time. When needed, the powder can be mixed with water to obtain a kind of thixotropic hydrogel in a very short time. Experimental results show this thermal protection technology with thixotropic ability has excellent thermal protection performance, meanwhile flexible, adhesive and low cost, which exerts instantaneous cooling, efficient thermal protection and long-lasting flame-retardant protection.展开更多
基金Funded by National Natural Science Foundation of China(No.52174206)Shaanxi Provincial Department of Education Youth Innovation Team Construction Scientific Research Plan Project(No.21JP074)Shaanxi Provincial Department of Education Youth Innovation Team Scientific Research Plan Project(No.22JP047)。
文摘Super absorbent resin(SAR)is prepared by aqueous high temperature polymerization using hydroxypropyl methylcellulose(HPMC)as monomer backbone material,acrylic acid(AA)and acrylamide(AM)as the graft copolymer monomer,potassium persulfate(KPS)as the initiator to generate free radicals,and N,N`-methylenebisacrylamide(MBA)as cross-linking agent for cross-linking reaction.Simutaneously,the influence of individual factors on the water absorption is investigated,and these factors are mainly AA,AM,KPS,MBA,HPMC,and reaction temperature.The optimized conditions are obtained by the experiment repeating for several times.The water absorption multiplicity and salt absorption multiplicity under the conditions are 782.4 and 132.5 g/g,respectivity.Furthermore,the effects of different temperatures and salt concentrations on its water absorption,as well as the swelling kinetics of SAR are studied.It is indicated the water-absorbing swelling process is mainly caused by the difference in water osmotic pressure and Na+concentration inside and outside the cross-linked molecular structure of the resin,which is not only consistent with the quasi-secondary kinetic model,but also with the Fick diffusion model.
文摘One of the ways of overcoming the cost of irrigation is through in-situ water harvesting at the plant roots. Super absorbent polymer (SAP) can facilitate water harvesting at the plant roots. This study attempted to assess the effect of SAP on plant available water (PAW) of different soils. In this study, SAP was sequentially added at the rate of 0.2%, 0.3% and 0.5% of the soil weight and its impact assessed in clay, sandy clay and sandy loam soils. The moisture retention characteristics of the original and SAP treated soils were studied using soil water retention curves (SWRC) and results modelled using Gardner model. PAW was estimated from SWRC as the difference between moisture content at 1.5 and 3 bar in all soils. The difference in PAW between original and treated soils was assessed at 5% level of significance. The WRC of all the samples was adequately found to be described by the Gardner model (Coefficient of determination R<sup>2</sup> ≥ 98% and residual standard error (RSE) ≤ 0.04). SWRC changed with increase in SAP percentage in clay, sandy clay and sandy loam soils. Clay had a higher change in water retention then sandy clay and lastly sandy loam. Plant available water content (PAW) in all soils increased. In clay soil it increased with increase in SAP from 0.3291 at zero SAP to 0.6223 at 0.5% SAP. Sandy clay soil increased in PAW from 0.2721 at zero SAP to 0.5335 at 0.5% SAP and Sandy loam soils from 0.1691 at zero SAP to 0.3461 at 0.5% SAP. Hence, from the study SAP can be used to conserve irrigation water in the plant roots and therefore reducing the cost since PAW has been increased.
基金Supported by Key Projects in the National Science&TechnologyPillar Program(2006BAD04B07-2)Sic-tech Innovation Projectof Hunan Academy of Agricultural Sciences(2009hnnkycx30)~~
文摘The effects of super absorbent polymers （SAP） on yield as well as water-saving and drought-escaping mechanism in spring maize in the seasonal drought region were studied. As shown by the results, during the seasonal drought in southern China, SAP treatment promoted the soil moisture, improved the capability of absorption and transportation of roots, promoted physiological and biochemical functions, increased the chlorophyll content, photosynthetic rate and intercellular CO2 concentration, and reduced the stomatal conductance and transplre.tion rate. As a result, the economic characters of spring maize were improved, and the yield was increased.
文摘The effect of super absorbent polymer（SAP） on the formation of tetrahydrofuran（THF） hydrate was studied by the successional cooling method.It was found that THF solution samples with 0.004 wt% and 0.03 wt% of SAP formed THF hydrate completely during the same cooling process.The corresponding induction time was 16-29 min,14-31 min,respectively,which was obviously shorter than that of THF solution samples without SAP（25-62 min）.It indicated that SAP accelerated the formation of THF hydrate.At the same time,the pictures of hydrate formation with and without SAP had been compared.It was found that SAP did not change the morphology of the hydrate.Finally,the mechanism of SAP promoting effect on the formation of THF hydrate was suggested.
文摘The grafting polyacrylamide onto wood pulp cellulose (cell g PAM) was performed with cerous ammonium nitrate as the initiator and hydrolyzed to produce the super absorbent resin. The FTIR shows that the polyacrylamide is grafted on the cellulose. After hydrolyzation, part of acrylamino groups are transformed into carboxyl groups. The XRD analysis shows that the graft polymerization occurred at the amorphous section and the surface of the crystal section of cellulose. The SEM graph reveals that there is a layer of polymer on the surface of cellulose fiber and the fibril structure of the cellulose surface is covered. After hydrolyzation, the surface of the product is different from that of cell g PAM's and the surface is scraggy. The technical conditions to prepare high water absorbent resin were confirmed. Through the radical graft copolymerization, the high water absorbent resin can be produced from wood pulp cellulose.
文摘A super absorbent material was prepared with the super absorbent resin （ SAR ） and inorganic gel. The SAR of the carboxymethyl cellulose grafting acrylic acid （ CMC-AA ） was copolymer synthesized using the method of inverse-phase suspension polymerization. The influences of the monomer concentration, neutralization degree, the initiator, dispersion agent, cross-linking agent, reaction and drying temperature on the grafting copolymer properties were examined. Meanwhlie, its properties was investigated and the model for absorption mechanism of this absorbent composite was proposed.
基金Basic Research Foundation of Beijing Institute of Technology (BIT-UBF-200504E4202)
文摘The two kinds of super absorbent resins from carboxymethyl cellulose were synthesized with the potassium persulphate and methylenebisacrylamide as initiator and cross linker respectively by radical polymerization in aqueous solution. Thestructures of the two resins were characterized with Fourier transform infrared spectroscopy FTIR, scanning electron miscroscopy （SEM）, and environment scanning electron miscroscopy （ESEM）, the results indicate that the fibriform of the carboxymethyl cellulose （CMC） is disappeared and the crusslink networks in eopolymer of carboxymethyl cellulose-graft-polyacrylic acid（CMC-g-PAA） are denser than that of eopolymer of carboxymethyl cellulose-graft-poly （acrylic acid-co-N-vinyl Pyrrolidone） （CMC-g- PAA-co-PVP）. The comparison between the two resins in absorption capacities is that CMC-g-PAA is better in the water-keep capability being heated, while CMC-g-PAA-co-PVP is better in the water absorbency and salt resistance.
文摘Due to large volume and high hardness of thermal insulation materials mostly used in high temperature fields, a composite cooling powder and its thixotropic hydrogel for thermal protection are presented. The core of composite cooling material powder is super absorbent polymer, composing with metal salt, polysaccharide hydrosol and inorganic particles and other modifiers through a series of composite process, which can be easily stored for a long time. When needed, the powder can be mixed with water to obtain a kind of thixotropic hydrogel in a very short time. Experimental results show this thermal protection technology with thixotropic ability has excellent thermal protection performance, meanwhile flexible, adhesive and low cost, which exerts instantaneous cooling, efficient thermal protection and long-lasting flame-retardant protection.
