Synthesis and characterization of thermosensitive composite microsphere latex

Monodisperse aqueous latex dispersions, prepared from mixtures of styrene, N‐isopropylacrylamide, and N,N′‐methylenebisacrylamide, were characterized. Thermosensitive composite microspheres with diameters greater than 1.0 μm, consisting of a polystyrene core and a poly(N‐isopropylacrylamide) shell, were prepared. The morphology of the composite microspheres was observed with transmission electron microscopy, and the particle size of the composite microspheres was estimated with dynamic light scattering. The thermosensitive properties of the composite microspheres were evaluated via the hydrodynamic size of the composite microspheres. The particle size of the composite microspheres decreased with increasing temperature. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 824–828, 2005     

Supercritical CO2‐assisted synthesis of poly(acrylic acid)/Antheraea pernyi SF blend

Monomer acrylic acid (AA) and initiator azo‐bis(isobutyronitrile)were carried into Antheraea pernyi silk fibroin (SF) fibers using supercritical CO₂ as a solvent and carrier, followed by free radical polymerization at a suitable temperature, resulting in PAA/SF blends. The binary system of CO₂/AA and the ternary system of CO₂/AA/AIBN systems were studied. Different impregnation conditions, such as time, pressure, and concentration of AA in the fluid phase on mass uptake, were studied. Fourier transform infrared spectroscopy and X‐ray diffraction results confirmed that PAA was indeed present in the silk and that there were intermolecular hydrogen bonds between PAA and SF. According to thermogravimetry and DTG, blending with PAA could enhance the thermal stability of SF slightly. The water retention values indicated that the hydrophilic nature of the fibers was improved. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 864–868, 2005     

Graft Copolymerization of Acrylamide onto Oil Palm Empty Fruit Bunch (OPEFB) Fiber

Grafting of acrylamide (AAm) onto oil palm empty fruits bunch fiber using hydrogen peroxide as initiator and methyl acrylate as comonomer was investigated. The amount of comonomer needed to make grafting of acrylamide possible was determined. The percentage of poly(acrylamide) and the comonomer in the final graft copolymer was estimated by elemental analysis. Results obtained indicated that methyl acrylate facilitated the incorporation of acrylamide monomer onto OPEFB. The reactivity ratios for both monomers were determined by using Fineman–Ross plot. The effects of reaction temperature and period as well as amount of the initiator, solvent, monomer and comonomer on the percentage of grafting at fixed amount of comonomer (11 mmol) were studied. Maximum percentage of grafting was achieved when the amount of initiator and solvent 3.98×10⁻³ mol and 50 mL respectively. The optimum reaction temperature was 50 ^○C and the reaction period was 90 min. Highest percentage of grafting was 232% when 25.6 mmol of acrylamide was used under these optimum conditions. The presence of functional group in the grafted polymer is characterized by infrared spectroscopy and the surface morphology is observed by scanning electron microscopy. Thermoanalytic investigation on OPEFB and OPEFB-g-PAAM were carried out to evaluate the thermal stability and respective activation energy of the materials.     

Barocalorimetric technique for monitoring pressurized copolymer reactors

The problem of on‐line estimation of the conversion and composition evolutions in a pressurized batch copolymer reactor with temperature and pressure measurements was addressed. The estimation model consisted of mass and energy balances with a pressure equation built from phase‐equilibrium considerations. The application of a nonlinear geometric estimation approach yielded the underlying solvability condition with physical meaning, a straightforward estimator construction, and a conventional‐like tuning procedure. The resulting barocalorimetric estimator was an on‐line dynamic measurement processor with a model‐based predictor and a measurement‐driven corrector, and whose implementation did not require the polymerization rates and heat‐transfer coefficient function dependencies. The technique was tested with a representative laboratory styrene–butadiene system. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 475–482, 2005     

原位乳液聚合制备聚苯乙烯丁二烯橡胶/凹凸棒石纳米复合材料

采用原位乳液聚合制备了聚苯乙烯丁二烯橡胶(SBR)/凹凸棒石(AT)纳米复合材料。凹凸棒石的存在一定程度上降低了乳液聚合速率,但对最终聚合产物的分子质量及分子质量分布影响不大。凹凸棒石以长0.5～5μm、直径为20～50nm的棒状纤维均匀的分散在SBR基体中。在硫化过程中,凹凸棒石纤维与橡胶形成互穿网络结构,增加了橡胶的交联密度。随着凹凸棒石的填充量增加,纳米复合材料的300%定伸应力和拉伸强度与纯SBR相比均提高了20%～100%,其补强效果明显高于等量的炭黑N330,还表现出良好的耐磨性能。     

MC尼龙/纳米Al2O3复合材料力学性能的研究

采用原位聚合技术制备了纳米Al2O3增强单体浇铸(MC)尼龙复合材料,用扫描电子显微镜观察其断口形貌纳米粒子分布状况,并测试、分析了纳米Al2O3含量对对材料力学性能的影响。结果表明，采用原位聚合技术可获得的纳米粒子分布均匀、综合性能优良的纳米复合材料，当纳米Al2O3质量分数的4%时，MC尼龙/纳米Al2O3复合材料的拉伸强度、冲击强度和弯曲强度均达到最大值，分别比纯MC尼龙提高了19%、33%和11%。     

间歇式聚丙烯装置产品熔体流动指数的控制

针对间歇式液相本体法聚丙烯装置的生产特点,根据实际生产经验,从原料、催化剂的选择与配方、升温操作、氢调、设备维护等对如何控制聚丙烯粉料熔体流动指数进行了分析。结果表明:只要控制得当,间歇式聚丙烯装置产品的熔体流动指数可以控制在(n±1.5)g/10min(n为预定值)的稳定范围。     

氨基甲酸酯基丙烯酸酯的合成及其光固化性能

利用碳酸亚乙酯与1,6-己二胺、异佛尔酮二胺反应，制备出两种含氨基甲酸酯基的二元醇，基于氨基甲酸酯二元醇与1,6-己二醇二丙烯酸酯（HDDA）、新戊二醇二丙烯酸酯（NPGDA）及三羟甲基丙烷三丙烯酸酯（TMPTA）本体条件下的Oxa-Michael加成反应及酯交换反应，合成出6种含氨基甲酸酯基的丙烯酸酯混合物。利用FTIR及高分辨质谱分析了产物结构，用FTIR考察了所合成氨基甲酸酯基丙烯酸酯光固化过程的动力学,测定了光固化膜的性能。结果表明，在含占总质量分数3% 的2-羟基-2-甲基-1-苯基-1-丙酮（1173）光引发剂的引发下，氨基甲酸酯基丙烯酸酯能在30s内固化形成表面平整、柔韧性（0.5~2.5mm）良好、透明或半透明的膜；固化膜的凝胶率及铅笔硬度分别为92%~96%、4~5H，对玻璃的附着力为0~1级。     

Polymerization of monomers initiated by silyl centers in SiO deposits prepared by pulsed laser ablation

Deposits from silicon monoxide prepared by pulsed laser ablation were allowed to react with acrylic and vinyl monomers—styrene, methyl methacrylate and 1,2 ethylene glycol dimethacrylate. It was revealed by means of FTIR, electron paramagnetic resonance (EPR), and NMR spectroscopies that silyl ?Si· reacts with monomer molecules and initiates the consecutive polymerization. Crosslinking is proved by the occurrence of bending δ(? CH₂) absorption peak at about 750 cm^?1 in FTIR spectra. Because of very low concentration of the propagating radical for styrene we used a radical scavenger N‐phenyl‐t‐butylnitrone for trapping. The measured EPR parameters were compared with the calculated ones. In case of styrene, NMR analysis manifested the presence of Si? C bonds in SiC_xO_y (x + y = 2) units, which can be taken as direct evidence of the reaction between silyl centers and monomer molecules. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4488–4492, 2006     

CDs/ZnO/g-C3N4三元组份协同作用促进光催化降解染料

采用浸渍-热聚合法制备CDs/ZnO/g-C3N4复合材料，考察其对罗丹明B的光降解效率。利用 XRD、TEM、XPS、UV-Vis DRS、FI-IR等手段对催化剂进行表征和评价。结果表明：CDs/ZnO/g-C3N4仍保持石墨相g-C3N4的晶型结构，三元组份相互协同作用使CDs/ZnO/g-C3N4表现出优异的光催化性能，其降解罗丹明B的效果优于单体g-C3N4、ZnO及ZnO/g-C3N4，脱色率可达到70%左右。