二苯基甲烷二异氰酸酯扩链改性聚碳酸亚丙酯

Chain Extension and Modification of Polypropylene Carbonate Using Diphenylmethane Diisocyanate

在转矩流变仪中,利用二苯基甲烷二异氰酸酯(MDI)对聚碳酸亚丙酯(PPC)进行扩链改性,利用元素分析仪、差示扫描量热仪、万能材料试验机、气体透过测试仪、水蒸气透过测试仪等仪器表征PPC改性前后的热性能、力学性能及其阻透性能。结果表明,PPC经MDI扩链改性后,其玻璃化转变温度(T_g)、拉伸性能以及阻透O_2、CO_2、H_2O性能得到提高;当MDI的含量达到5%(质量分数,下同)时,PPC的T_g由未改性前的30.37℃提升至33.48℃,拉伸强度从20.9 MPa提高到49.0 MPa,O_2透过量从15.8×10^(-5)cm^3/m^2d·Pa降至5.8×10^(-5)cm^3/m^2d·Pa,CO_2透过量从38.6×10^(-5)cm^3/m^2d·Pa降至15.0×10^(-5)cm^3/m^2 d·Pa,水蒸气透过量从23.7 g/m^2·d降至10.3 g/m^2·d。

Polypropylene carbonate （PPC） was chemically modified by use of diphenylmethane diisocyanate （MDI） as a chain extender in an internal mixer, and then the thermal performance, mechanical behavior and barrier behavior of the modified PPC were investigated by means of elemental analysis,differential scanning calorimetry, universal material testing machine,gas permeability tester, water vapor permeability tester and other instruments. The results indicated that the glass transition temperature （Tg）, mechanical properties, and O2,CO2 and H2O barrier properties of PPC were enhanced due to the chemical modification. Tg of PPC was increased from 30. 37 ℃ to 33. 48 ℃ in the presence of 5 % MDI, and meanwhile,the tensile strength was improved from 20. 9 MPa to 49. 0 MPa. Moreover 02 permeability of PPC decreased from 15. 8× 10-5 cm3/m2d· Pa to 5. 8×10-5 cm3/m2d · Pa, CO2 permeability decreased from 38. 6× 1 0-5 cm3/ m2d . Pa to 15. 0×10-5 cm3/m2d · Pa,and water vapor transmission rate decreased from 23. 7 g/ m2 · d to 10. 3 g/m2· d.