Antimicrobial Expanded Polytetrafluoroethylene Film Prepared by 3-ray Radiation Induced Grafting of Poly（acrylic acid）

The simultaneous γ-ray-radiation-induced grafting polymerization of acrylic acid on ex- panded polytetrafluoroethylene （ePTFE） film was investigated. It was found that the degree of grafting （DG） of poly（acrylic acid） （PAA） can be controlled by the monomer concentration, absorbed dose, and dose rate under an optimal inhibitor concentration of [Fe2＋]=18 mmol/L. SEM observation showed that the macroporous structure in ePTFE films would be covered gradually with the increase of the DG of PAA. The prepared ePTFE-g-PAA film was im- mersed in a neutral silver nitrate solution to fabricate an ePTFE-g-PAA/Ag hybrid film after the addition of NaBH4 as a reduction agent of Ag＋ to Ag atom. SEM, XRD, and XPS results proved that Ag nanoparticles with a size of several tens of nanometers to 100 nanometers were in situ immobilized on ePTFE film. The loading capacity of Ag nanoparticles could be tuned by the DG of PAA, and determined by thermal gravimetric analysis. The quart- titative antibacterial activity of the obtained ePTFE-g-PAA/Ag hybrid films was measured using counting plate method. It can kill all the Escherichia coli in the suspension in 1 h. Moreover, this excellent antibacterial activity can last at least for 4 h. This work provides a facile and practical way to make ePTFE meet the demanding antimicrobial requirement in more and more practical application areas.

Covalent Functionalization of Multiwalled Carbon Nanotubes with Poly（acrylic acid）

Covalent functionalization of multiwalled carbon nanotubes （MWNT） with poly（acrylic acid） has been successfully achieved via grafting of poly（acryloyl chloride） on nanotube surface by esterification reaction of acyl chloride-bound polymer with hydroxyl functional groups present on acid-oxidized MWNT and hydrolysis of polymer attached to nanotubes. Polymer-functionalized MWNT could possess remarkably high solubility in water, and their aqueous solution was very stable without any observable black deposit for a long time. Characterizations of such functionalized MWNT samples using Fourier transform infrared spectrometer, transmission electron microscopy and nuclear magnetic resonance techniques indicated that poly（acrylic acid） was covalently attached to the surface of MWNT.

Synthesis and Properties of IPN Hydrogels Based on Konjac Glucomannan and Poly(acrylic acid)

Novel interpenetrating polymer network （IPN） hydrogels based on konjac glucomannan （KGM） and poly（acrylic acid） （PAA） were prepared by polymerization and cross-linking of acrylic acid （AA） in the pre-fabricated KGM gel. The IPN gel was analyzed by FF-IR. The studies on the equilibrium swelling ratio of IPN hydrogels revealed their sensitive response to environmental pH value. The results of in vitro degradation showed that the IPN hydrogels retain the enzymatic degradation character of KGM.

Swelling Behaviors of Polyaniline-Poly(Acrylic Acid) Hydrogels

Using poly（acrylic acid） （PAA） aqueous solution, NaOH aqueous solution, aniline （An） and ammonium persulfate （APS）, PAn-PAA hydrogels with a semi-interpenetrating structure connected by physical interlocks, chemical ion bonds and hydrogen bonds were prepared. The swelling properties of the hydrogels in solutions of different pH values （adjusted by adding NaOH or HCI） were studied. All the hydrogels prepared have similar swelling curves （the curves of equilibrium swelling ratio vs. pH value） and reach their maximum swelling at pH of 8 - 10. The maximum swelling ratio of the hydrogels is dependent on composition, including molecular weight of PAA, polymer content of the hydrogel, and molar ratios of AA to An, APS to An, and NaOH to AA, And the compositional dependence of the swelling capacity of PAn-PAA hydrogels was also studied.

Highly Stretchable and Self-healing Hydrogels Based on Poly(acrylic acid) and Functional POSS

Herein, we present a novel way for the production of self-healing hydrogels with stretch beyond 4200% than their initial length and relatively high tensile strength （0.1-0.25 MPa）. Furthermore, the hydrogel was insensitive to notch. Even for the samples containing V-notches, a stretch of 2300% was demonstrated. The hydrogels were developed by in situ crosslinking of the self-assembled colloidal poly（acrylic acid） （PAA）/functionalized polyhedral oligomeric silsesquioxane （POSS） micelles. This was achieved by the addition of functionalized polyhedral oligomeric silsesquioxane with tertiary amines and hydroxyls （POSS-AH） into the PAA reaction solution. The POSS-AH led to micellar growth, then the dual- crosslinked network was constructed. One type of crosslink was formed by hydrogen-bonding and ionic interactions between PAA chains and POSS-AH, the other type of crosslink was formed by covalent bonds between PAA and bis（N,N＇-methylene- bis-acrylamide）.

有机硅氧烷改性丙烯酸乳液的研究

用含不饱和双键有机硅单体与丙烯酸酯单体共聚,使乳液的性能得到改观.着重研究了乳化剂的用量及其配比,丙烯酸单体的用量,有机硅功能单体种类、用量及聚合工艺对乳液及涂膜性能的影响.

Micro-Friction of Diazoresin/Polyacrylic Acid Self-Assembly Films in Water with Atomic Force Microscopy

Ultrathin films composed of diazoresin（DR）and polyacrylic acid（PAA）were fabricated.The surface morphology of the films in water was measured using an atomic force microscopy（AFM）.The self-assembly technique makes the surface rather flat and uniform.The friction force and its dependence on the velocity differ from the surface charge of the thin films.The friction force of repulsive DR/PAA film increases linearly with velocity and has lower values than that of attractive DR film over the full range of velocity.As the velocity increases,the attractive friction of DR film first decreases to a minimum at a velocity of 2 line/s and then increases all the way.When the surface is repulsive to the friction substrate,the friction of thin films that is determined by hydrated lubrication of polymer chains that is ultralubricated;when it is adhesive to the friction substrate,the friction is mainly contributed from the elastic deformation of adsorbed polymer chains in the low velocity region and from viscous sliding in the presence of hydrated-layer lubrication of the polymer chains in the higher velocity region.

光辅助引发制备低粘均相对分子质量聚丙烯酸钠

以丙烯酸(AA)和氢氧化钠为原料,过硫酸铵、亚硫酸氢钠为引发剂,采用光辅助引发聚合法对聚丙烯酸钠的制备进行了研究。研究了AA单体、引发剂及链转移剂的用量、反应温度和反应时间等对产物粘均相对分子质量的影响。结果表明,反应温度为30℃、w(AA单体)=20%、w[(NH4)2S2O8]=0.05%、w(NaHSO3)=2.0%、光源距离15cm,可制得聚丙烯酸钠的粘均相对分子质量在2 100~2 500,单体转化率在97%以上。

硅丙乳液及硅丙外墙涂料的研制

用水解抑制和后交联控制技术 ,将有机硅氧烷和聚硅氧烷引入丙烯酸树脂的主链中 ,共聚合成AB -1硅丙乳液 ,该乳液中的有机硅含量达到20%以上。以AB -1硅丙乳液为基料生产的水性硅丙外墙涂料 ,具有优异的耐候性、抗沾污性、憎水性及附着力等 。