Synthesis and surface modification of the nanoscale cerium borate as lubricant additive

Nanoparticle of cerium borate with a size of about 50 nm was synthesized via sol-gel precipitation method under micro-emulsion by oleic acid,using Na2B4O7 and Ce(NO3)3 aqueous solution as raw materials,and the morphology and microstructure of as-prepared particles were characterized by means of scanning electron microscopy(SEM) equipped with an energy-dispersive X-ray spectrometer(EDS),X-ray diffraction(XRD),infrared spectroscopy(IR),and thermogravimetric analysis(TGA).Two methods to disperse the particles into base oil were employed,and the results derived from the four-ball tribotester indicated that the friction coefficient of the base oil by the addition of the nanoscale cerium borate particles diminished greatly,and the anti-wear properties also depended on the dispersion methods.     

壳聚糖/聚氨酯树脂的制备及对Cu2+吸附研究

以壳聚糖和聚氨酯预聚体为原料制备了壳聚糖/聚氨酯树脂(CTS/PU),考察了其对铜离子吸附性能。结果表明,CTS/PU树脂表面较粗糙;随预聚体用量增大,树脂吸附量先增加后降低。CTS/PU比例为1∶1时,树脂对Cu2+吸附量可达到优;pH值为6时,树脂对Cu2+吸附量最大。动力学研究表明,树脂对Cu2+吸附过程符合准二次动力学模型。     

聚乳酸/三乙酸甘油酯的热力学和老化性能研究

采用熔融共混法,以三乙酸甘油酯(GTA)作为增塑剂改性非晶聚乳酸(PLA)。研究了PLA/GTA的热力学性能、老化性能和热稳定性。讨论了GTA用量对非晶PLA性能的影响。当GTA含量增加时,材料的玻璃化转变温度降低,拉伸强度下降,断裂伸长率增加。当GTA质量分数为15%时,材料发生脆韧转变,且此时材料的性能较优。老化实验结果表明,在60℃老化7 d后,材料发生了结晶,GTA和PLA的相容性变差,但未出现明显的相分离。热失重测试显示,PLA/GTA的降解温度高于GTA的降解温度。     

PESU—C／UHMWPE共混合金的力学性能

研究了PESU-C/UHMWPE共混合金的力学性能与其组成及相态结构的关系。实验表明,在PESU-C中加入少量UHMWPE不仅极大地改善了PESU-C的冲击性能,而且对拉伸性能和加工流动性也有明显的改善,而UHMWPE含量超过2％时,共混体系的性能有不同程度降低。相态结构分析表明,UHMWPE作为分散相在低含量时以细微的粒子形态均匀分布于PESU-C基体之中,相态结构稳定,体系的力学性能最佳;随着UHMWPE含量的增加,分散相逐渐聚集为微纤状结构,并最终发展为双连续相结构,相态的不稳定性导致了共混体系力学性能降低。