复合发泡体系对PUR-T发泡材料性能的影响

摘要

Thermoplastic polyurethane (PUR–T) foaming materials were prepared with PUR–T,the composite foaming agents of azodicarbonamide (AC)/NaHCO3,AC/urea,4,4'–oxybis(benzenesulfonyl hydrazide) (OBSH)/NaHCO3,OBSH/urea and the cross linker of toluene diisocyanate (TDI). The foaming effects of different composite foaming agents were compared by uni-versal electronic testing machine,foaming multiples and scanning electron microscopy. The effects of AC/NaHCO3 dosage ratio and TDI dosage on mechanical properties,foaming multiples and pore structure of PUR–T foaming material were investigated. The results show that AC / NaHCO3 composite foaming agent has the best foaming effect on PUR–T. The pores are uniform and fine, and the structure is the most stable. When the dosages of AC and NaHCO3 are 0.2 phr and the dosage of TDI is 1.2 phr,the foaming rate of the foaming agent is best matched with the crosslinking rate of PUR–T,the foaming multiple is 1.421 times,the best foaming effect and the mechanical properties of PUR–T foam material are the best,the tensile strength is 11.23 MPa and the elongation at break is 311%.%采用化学发泡法,用热塑性聚氨酯(PUR–T)及偶氮二甲酰胺(AC)/NaHCO3,AC/尿素及4,4'– 氧代双苯磺酰肼(OBSH)/NaHCO3,OBSH/尿素复合发泡剂和交联剂甲苯二异氰酸酯(TDI)制备出交联型PUR–T发泡材料,通过万能电子试验机、发泡倍数和扫描电子显微镜分析比较了不同复合发泡剂的发泡效果,探讨了AC/NaHCO3用量配比和TDI用量对PUR–T发泡材料力学性能、发泡倍数和泡孔结构的影响.结果表明,AC/NaHCO3复合发泡剂对PUR–T的发泡效果最佳,泡孔均匀细密且结构最为稳定;当AC和NaHCO3用量均为0.2份、TDI用量为1.2份时,发泡剂的发泡速率和PUR–T的交联速率最匹配,发泡倍数为1.421倍,发泡效果最佳,制得的PUR–T发泡材料的力学性能最好,其拉伸强度达11.23 MPa,断裂伸长率达311%.