Kong Xiaohua, Narine Suresh S
Alberta Lipid Utilization Program, Department of Agricultural Food and Nutritional Science, 4-10 Agriculture/Forestry Centre, University of Alberta, Edmonton, Alberta, Canada.
Biomacromolecules. 2007 Jul;8(7):2203-9. doi: 10.1021/bm070016i. Epub 2007 Jun 6.
Polyurethane (PUR) plastic sheets were prepared by reacting polyols synthesized from canola oil with aromatic diphenylmethane diisocyanate. The properties of the material were measured by dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA) as well as tensile properties measurements. The effect of stoichiometric balance (i.e., OH/NCO molar ratio) on the final properties was evaluated. The concentration of elastically active network chains (EANCs), nue, of the polymer networks was calculated using rubber elasticity theory. The glass transition temperatures (Tg) for the plastic sheets with OH/NCO molar ratios of 1.0/1.0, 1.0/1.1, and 1.0/1.2 were found to be 23, 41, and 43 degrees C, respectively. The kinetic studies of the degradation process of the PUR plastics showed three well-defined steps of degradation. The PUR plastic sheets with OH/NCO molar ratio 1.0/1.1 had the highest nue, lowest number-average molecule weight between cross-links, MC, and excellent mechanical properties, indicating that this is the optimum ratio in the PUR formulations.
通过使由菜籽油合成的多元醇与芳族二苯基甲烷二异氰酸酯反应制备聚氨酯（PUR）塑料片材。通过动态力学分析（DMA）、差示扫描量热法（DSC）、热重分析（TGA）以及拉伸性能测量来测定材料的性能。评估化学计量平衡（即OH/NCO摩尔比）对最终性能的影响。使用橡胶弹性理论计算聚合物网络的弹性活性网络链（EANC）浓度nue。发现OH/NCO摩尔比为1.0/1.0、1.0/1.1和1.0/1.2的塑料片材的玻璃化转变温度（Tg）分别为23、41和43摄氏度。PUR塑料降解过程的动力学研究显示出三个明确的降解步骤。OH/NCO摩尔比为1.0/1.1的PUR塑料片材具有最高的nue、最低的交联间数均分子量MC以及优异的机械性能，表明这是PUR配方中的最佳比例。
