纳米碳酸钙改性用超支化聚酯的合成及表征研究

Synthesis and characterization of hyperbranched polyester used as modifier of nano calcium carbonate

以柠檬酸和聚乙二醇6000为原料,对甲苯磺酸为催化剂,两步法合成超支化聚酯,作为纳米碳酸钙的改性剂。以提高聚酯的特性黏度[η]为目标,对反应条件进行优化,优化结果为反应温度160℃,催化剂用量为原料总质量的3.0%,第一阶段常压反应3h,减压1h,第二阶段常压和减压均为3h。减压反应压强均为0.6kPa。对优化条件下产物测定[η]和酸值,并进行了FT-IR、GPC、TGA和DSC测试。结果表明[η]较高,为37.6mL/g,羧基酯化率为58.7%,数均分子量Mn为37.1×103,重均分子量Mw为77.6×103,在269.1℃以下仅失重3.0%,熔融温度Tm为51.0℃,结晶温度Tc为22.6℃,玻璃化转变温度Tg为-21.8℃。超支化聚酯改性纳米碳酸钙对淀粉基生物降解塑料增强效果明显。

As a kind of modifier of nano calcium carbonate（NCC）,hyperbranched polyester was synthesized by citric acid and polyethylene glycol 6000 with catalyst p-toluenesulfonic acid in a two-step reaction.Reaction conditions were optimized to improve intrinsic viscosity（[η]）of polyester.The optimized conditions were as follows：reaction temperature was 160℃,the amount of catalyst was 3.0% of the total mass of reactants,the time of first period was 3hat atmospheric pressure and 1hunder vacuum,the time of second period was 3hat atmospheric pressure and 3hunder vacuum.The pressure was 0.6kPa.The optimized product was characterized by FT-IR,GPC,TGA and DSC.The result showed that its esterification ratio reached 58.7%,[η]was 37.6mL/g.Mn was 37.1×10^3,Mwwas 77.6×10^3.There was only 3.0% weight loss below 269.1℃.Tm,Tc,Tgwere 51.0℃,22.6℃,-21.8℃,respectively.NCC modified by hyperbranched polyester synthesized successfully reinforced starch-based plastic.