Department of Chemistry, School of Science, Xi'an Jiaotong University, Xi'an 710049, China.
Carbohydr Polym. 2013 Oct 15;98(1):1056-64. doi: 10.1016/j.carbpol.2013.07.015. Epub 2013 Jul 16.
The latex of silane-fluoroacrylate grafted starch for coating materials, VTMS-starch/P(MMA/BA/3FMA), is obtained by two step grafting reactions. Vinyltrimethoxysilane (VTMS) is primarily grafted onto starch by condensation between Si-OH and C-OH at 120 °C, and then the copolymer of methyl methacrylate (MMA), butyl acrylate (BA) and 2,2,2-trifluoroethyl methacrylate (3FMA) is grafted onto the VTMS-starch by emulsion polymerization. Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS) have been used to confirm the chemically grafting reactions in every step. The conversion percent, grafting percent and grafting efficiency for VTMS-starch/p(MMA/BA/3FMA) latex indicate that the optimum conditions should be controlled at 75 °C for 1h as VTMS-starch/P(MMA/BA/3FMA) in 1/3 weight ratio. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis have revealed that the latexes exhibit the uniform spherical particles of 40-60 nm in a narrow size distribution. The latex films perform the obvious hydrophobic (107°) property, lower surface free energy (25-35 mN/m) and the higher thermostability (330-440 °C) than starch (51°, 51.32 mN/m, 100-330 °C). Dynamic thermomechanical analysis (DMA) shows that the latex film could gain considerable toughness and strength with an elongation at break of 39.45% and a tensile strength of 11.97 MPa.
用于涂料材料的硅烷-氟丙烯酸酯接枝淀粉的乳液，VTMS-淀粉/P（MMA/BA/3FMA），是通过两步接枝反应得到的。乙烯基三甲氧基硅烷（VTMS）主要通过 120°C 下 Si-OH 和 C-OH 之间的缩合反应接枝到淀粉上，然后甲基丙烯酸甲酯（MMA）、丙烯酸丁酯（BA）和 2,2,2-三氟乙基甲基丙烯酸酯（3FMA）的共聚物通过乳液聚合接枝到 VTMS-淀粉上。傅里叶变换红外光谱（FTIR）和 X 射线光电子能谱（XPS）已被用于证实每一步的化学接枝反应。VTMS-淀粉/p（MMA/BA/3FMA）乳胶的转化率、接枝率和接枝效率表明，最佳条件应控制在 75°C 下 1h，VTMS-淀粉/P（MMA/BA/3FMA）的重量比为 1/3。透射电子显微镜（TEM）和动态光散射（DLS）分析表明，乳胶表现出均匀的 40-60nm 粒径分布的球形颗粒。乳胶膜表现出明显的疏水性（107°）、较低的表面自由能（25-35mN/m）和较高的热稳定性（330-440°C），而淀粉的疏水性为 51°、表面自由能为 51.32mN/m、热稳定性为 100-330°C。动态热机械分析（DMA）表明，乳胶膜具有相当大的韧性和强度，断裂伸长率为 39.45%，拉伸强度为 11.97MPa。
