摘要
以聚醚二元醇(PEG)、甲苯二异氰酸酯(TDI)、端羟基硅油(GY-23)为主要原料,经共聚反应,当N-甲基二乙醇胺(ZC-10)用量质量比为5.87%时,制得中位粒径0.72μm的羟基硅油改性嵌段阳离子聚氨酯(GRK)稳定的棕色乳液,胶膜呈浅棕色不透明。经FT-IR、1H-NMR对产物进行表征,确认GRK分子结构中含-C6H3(CH3)-NH-COO-(Si(CH3)2-O-)n-结构单元(Ⅰ)。紫外-可见光分光光度计分析表明结构单元(Ⅰ)是显色基团,在波长325.2nm处有强吸收,摩尔吸收系数lgε=0.425。在结构单元(Ⅰ)中的-ArNHCOO与聚二甲基硅氧烷相连,硅的电负性比碳小,是σ-给电子基,能明显地降低碳基的电离势,提高了非键轨道n轨道的能量,同时硅原子的d轨道与氧原子的p轨道重叠,降低了π*轨道的能量,因而降低了激发能级,提高了聚合物对光吸收的几率。
Polysiloxane modified cationic water-bone polyurethane （GRK） latex was prepared by condensation polymerization of polyethylene glycol （Mn=1000）, 2,4-tolyerne diisocyanate （TDI） and hydroxyl terminated organ-silicone. With 5.87 %（wt） N-methyldiethanolamine （ZC-10）, the obtained latex is stable and has a brown color with the average particle size of 0.724 μm, and the coating formed from it is opaque and has light brown color. Using FT-IR and ^1H-NMR techniques, the structure unit, -C6H3（CH3）-NH-COO-（Si（CH3）2- O-）n- （Ⅰ）, incorporated in the polymer was identified, and by the help of the UV-visible spectrophotometer, the fact that the unit （Ⅰ） in the polymer is a chromogenic group with the maximum absorbed wave length of λmax =325.2 nm and molar absorbance coefficient of 1g ε=0.425 was identified. In unit （Ⅰ）, -ArNHCO- is connected with polysiloxane, and since the eletregativity value of the siloxane atom is smaller than that of carbon, the siloxane is a a-electron donating group which can obviously lower the electronicrocess potential of the carbon atom and can increase the energy of non-linkage n-orbit. At the same time, d-orbit of Si atom overlap with porbit of oxygen atom, which reduces the energy of π^＊-orbit and hence lowers the excited energy band gap of n→π^＊ transition and increases the light absorption and the εmax value of the polymers.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2007年第1期126-130,共5页
Journal of Chemical Engineering of Chinese Universities
基金
浙江省科技厅科技计划项目(2002C31006)
关键词
聚硅氧烷
改性聚氨酯
显色机理
涂料
polysiloxane
modified polyurethane
color structure unit
coating
