title: Synthesis and properties of silane-fluoroacrylate grafted starch.
abstract: 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.
authors.affiliation: Department of Chemistry, School of Science, Xi'an Jiaotong University, Xi'an 710049, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Qu
authors.forename: Ling
authors.initials: L
authors.lastname: He
mesh_terms: D000179:Acrylates / Q000737:chemistry*; D060326:Chemistry Techniques, Synthetic; D006244:Hardness; D007840:Latex / Q000737:chemistry; D008768:Methylmethacrylates / Q000737:chemistry*; D019904:Polymethyl Methacrylate / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry*; D013213:Starch / Q000138:chemical synthesis* / Q000737:chemistry*; D013816:Thermodynamics; D014753:Vinyl Compounds / Q000737:chemistry*; D017155:Wettability
chemical_list: D000179:Acrylates; D007840:Latex; D008768:Methylmethacrylates; D012821:Silanes; D014753:Vinyl Compounds; C529208:trimethoxyvinylsilane; C045669:2,2,2-trifluoroethyl methacrylate; C032490:n-butyl acrylate; D013213:Starch; D019904:Polymethyl Methacrylate
keywords: Fluoroacrylate copolymer; Mechanical properties; Morphology of latex; Silane coupling agent; Starch; Surface properties; Thermostability