盐酸含量对光固化聚氨酯丙烯酸酯/SiO2杂化材料结构和性能的影响

由正硅酸乙酯水解制得的SiO2溶胶，在以γ—甲基丙烯酰氧丙基三甲氧基硅烷(TMSPM)为偶联剂的体系中，经溶胶-凝胶法制备了透明的光固化聚氨酯丙烯酸酯杂化材料[(PUA—TMSPM)／SiO2]。研究了盐酸浓度对(PUA-TMSPM)／SiO2结构与性能的影响。结果表明：随着pH值减小，硅溶胶体系和(PUA-TM-SPM)／SiO2杂化体系的热稳定性增大；盐酸摩尔分数XHCl的增加使(PUA-TMSPM)／SiO2光固化膜表面的两相界面结合更紧密，涂层变得更致密，并导致膜的硬度和耐磨性提高。     

无机纳米粒子/丁苯胶乳复合技术的研究

研究了无机纳米粒子／丁苯胶乳的复合材料，用脂肪酸对纳米粒子进行了表面改性，使之均匀分散在丁苯胶乳中，用红外、吸油性，润湿试验等方法对改性纳米微粒进行了表征，纸张涂布和老化试验证明，纳米碳酸钙和纳米氧化锌具有优良的隔热效果，纳米氧化锌还有很好的防紫外老化功能，对以纳米TiO2为核，包覆苯丙共聚物的乳液矣合也作了初步研究。     

壳聚糖修饰玻碳电极卷积伏安法测定环境水中的EDTA

制备了壳聚糖修饰玻碳电极 ,研究了Fe(EDTA) -在修饰电极上的吸附还原行为 ,用卷积伏安法通过Fe(EDTA) -的检测测定了环境水中的EDTA。在优化的实验条件下 ,峰电流值与 8.0× 1 0 -7～ 5 .0× 1 0 -6mol L的EDTA呈线性关系 ,回归方程为epp′ =0 .75 2 5c - 0 .661 3,r =0 .991 ,最低检出限为 5 .0× 1 0 -7mol L ,5次测定的相对标准偏差小于 5 .8%。对实际样品测定的回收率为98 1 %～ 1 0 5 % ,对比HPLC的结果 ,相对偏差小于 5 %。     

THE SYNTHESIS OF MODIFIED DIPHENYL OXIDE RESIN

1. INTRODUCTION Poly (diphenyl oxide) (DPO) resins are a series of heat-resisting thermosetting resins. In 1960s, the West House Company applied them to make H class insulting materials and got an extensive use successfully [1]. But due to the three main…     

Synthesis and kinetics of polymerization of unsaturated monomers with OH groups in their structure: I.3-hydroxyneopentyl acrylate

The synthesis of new unsaturated monomers containing functional groups has been theoretically analyzed by considering a simple kinetic scheme. In the reactions between acetyl and acryloyl chloride with neopentylglycol, it was shown that the comparison between theoretical and experimental results, does not allow us to conclude that the two rate constants controlling the reactions are equivalent. Kinetic experiments of the polymerization of 3-hydroxyneopentyl acrylate were carried out in benzene and 1,4-dioxane solution at different temperatures. Dilatometric techniques and nonlinear least-squares methods were used to obtain kinetic data and to determine the kinetic constants, respectively. The values of $k_p /k_t^{1/2}$ for this monomer were found higher in dioxane than in benzene due, probably, to the fact that in the last solvent the polymerization is heterogeneous. The activation energy, determined by using different values of $k_p /k_t^{1/2}$ was found 7.6 kcal/mol. The stereostructure of the polymers derived from 3-hydroxyneopentyl acrylate and 3-acetoxyneopentyl acrylate was determined by ¹³C-NMR spectroscopy from the analysis of the resonance signals belonging to the carbonyl groups, obtaining values for the fraction of isotactic dyads in the range 0.36 ± 0.03 for both polymers. Finally, the glass transition temperatures of both polymers, determined calorimetrically, were found 281 and 255 K, respectively. © 1994 John Wiley & Sons, Inc.     

Immobilization of endo-1,4-β-xylanase on polysulfone acrylate membranes: Synthesis and characterization

We report on a new enzyme/support system to immobilize proteins such as enzymes through a covalent bond on polysulfone membranes. In the present case the enzyme endo-1,4-β-xylanase (E.C.3.2.1.8) is attached to polysulfone previously derivatized by introducing an acrylate group. Membranes are properly prepared from this polysulfone acrylate. Afterwards the enzyme is immobilized though the amino groups of side chains of the amino acids of the enzyme and the acrylate group of the derivatized polysulfone. Such immobilization of the enzyme is confirmed by microelemental analysis as well as by amino acid analysis by HPLC. Moreover, the enzymatic activity of the membranes was evaluated and compared with that corresponding to the free enzyme. Certain physical parameters (asymmetry, irregularity, pore size and surface roughness) of the corresponding enzymatic membranes were obtained from SEM and AFM image interpretation.     

Thermal Emulsion Polymerization without any Conventional Initiators and Emulsifiers

Stable poly(styrene-co-sodium styrene sulfonate) (P(St-NaSS) nanoparticles with broader size distribution were synthesized by thermal emulsion polymerization without any conventional initiators and emulsifiers. The obtained polymer nanoparticles have higher ξ potential, and the particle sizes have broad distribution. The stability of polymer particles originated from the addition of small amounts of ionic comonomer, NaSS, which can act as an emulsifier in somewhat. The monomer conversion could reach up to about 28 wt% in 48 h, and did not increase by further polymerization when higher polymerization temperature (120 ℃) was employed. This polymerization system may be give some further understand for mechanism of emulsion polymerization.     

Thermal degradation of vinylidene chloride/[4-(t-butoxycarbonyloxy)phenyl]methyl acrylate copolymers

Vinylidene chloride polymers containing comonomer units capable of consuming evolved hydrogen chloride to expose good radical-scavenging sites might be expected to display greater thermal stability than similar polymers containing simple alkyl acrylates as comonomer. Incorporation of a comonomer containing the phenyl t-butyl carbonate moiety into a vinylidene chloride polymer has the potential to afford a polymer with pendant groups which might interact with hydrogen chloride to expose phenolic groups. Copolymers of vinylidene chloride with [4-(t-butoxycarbonyloxy)phenyl]methyl acrylate have been prepared, characterized, and subjected to thermal degradation. The degradation has been characterized by thermal and spectroscopic techniques. The degradation of vinylidene chloride/[4-(t-butoxycarbonyloxy)phenyl]methyl acrylate copolymers is much more facile than the same process for similar copolymers containing either [4-(isobutoxycarbonyloxy)phenyl]methyl acrylate or methyl acrylate, a simple alkyl acrylate, as comonomer. During copolymer degradation, [4-(t-butoxycarbonyloxy) phenylmethyl acrylate units are apparently converted to acrylic acid units by extensive fragmentation of the sidechain. Thus, the phenyl t-butyl carbonate moiety does function as a labile acid-sensitive pendant group but its decomposition in this instance leads to the generation of a phenoxybenzyl carboxylate capable of further fragmentation.     

A New Kind of Void Soap-free P（MMA-EA-MAA） Latex Particles

Soap-flee P(MMA-EA-MAA) particles with narrow size distribution were synthesized by seeded emulsion polymerization of methyl methacrylate (MMA), ethyl acrylate (EA) and methacrylic acid (MAA), and large voids inside the particles were generated by alkali posttreatment in the presence of 2-butanone. Results indicated that the size of void and theparticle volume were related with the amount of 2-butanone. The generation mechanism of voids was proposed.     

Fluorinated monomer–styrene copolymer latex particles: I. kinetic studies in a soap-free aqueous medium

Soap-free emulsion copolymerization of 2, 2, 2-trifluoroethyl acrylate (3FEA) with styrene was carried out by using potassium persulfate as an initiator, and the effects of the weight fraction of 3FEA in the monomer feed on the kinetics and the particle size were investigated. Monomer conversions were followed by a gravimetric method, revealing that the overall polymerization rate increased exponentially with an increase in the weight fraction of 3FEA. According to dynamic light scattering measurement, the final particle size was found to decrease with an increase in the weight fraction of 3FEA. The number of particles for 3FEA homopolymerization was roughly twice as large as that at the fraction of 0.9, although both fractions had the almost same polymerization rates. These results indicate that soap-free emulsion homopolymerization of 3FEA would proceed not only inside the polymer particles but also in the aqueous phase throughout the polymerization.