氨基甲酸酯基/脲键对混合TDI聚酯-聚氨酯树脂羰基氢键作用的影响

Effect of Urethane/Urea on Carbonyl Hydrogen Bonding of Polyester-Polyurethane Resin with Mixed TDI

以聚己二酸-2-甲基-2,4戊二醇酯二醇(XCP-2000PM)为软段,以2,4-2,6混合甲苯二异氰酸酯(TDI,T-80)、异佛尔酮二胺(IPDA)和乙二醇(EG)、1,2-丙二醇(PG)、1,4-丁二醇(BDO)、新戊二醇(NPG)为硬段,制备了系列具有不同氨基甲酸酯基/脲键的聚酯型聚氨酯树脂,采用傅里叶变换红外光谱(FTIR)研究在总硬段含量不变的情况下,酯羰基、氨基甲酸酯基/脲键、混合甲苯二异氰酸酯结构对羰基氢键的影响。结果表明,在聚酯多元醇酯羰基的作用下,聚酯型聚氨酯树脂的氨酯羰基与酯羰基区红外光谱存在6个吸收峰,聚酯多元醇结构中的内部酯羰基不形成氢键,外部酯羰基部分形成氢键,氢键化程度随着小分子二元醇扩链比例的提高由5%升至9%。在硬段含量为20%时,聚酯型聚氨酯树脂以游离氨酯羰基与酯羰基为主,二者之和在60%左右。在2,4-2,6混合甲苯二异氰酸酯不对称结构的影响下,随着氨基甲酸酯基/脲键的增大,氨酯羰基与脲羰基的氢键化程度降低,游离氨酯羰基、酯羰基与脲羰基增多,微相分离程度减弱,软硬段混合程度增强;总体上脲羰基的氢键化程度所占比例较小,一般在6%左右;而P-PU在扩链比例为0.25时,氨酯羰基的氢键化程度较大,而后减小。

A series of different urethane/urea polyester polyurethanes(polyester-PU)with various diols were synthesized by poly(2-methyl-2,4-pentadiol adipate)diol as soft segment,2,4-2,6 mixed toluene diisocyanate(TDI T-80),isophorone diamine(IPDA),glycol(EG),1,2-propylene glycol(PG),1,4-butanediol(BDO)and neopentyl glycol as hard segment.Fourier transform infrared(FTIR)spectroscopy was used to investigate the effect of ester carbonyl,carbamate/urea linkages,and mixed toluene diisocyanate structures on carbonyl hydrogen bonding under the constant total hard segment content.The results showed that in the role of polyester polyol ester carbonyl group,there are six absorption peaks in the infrared spectra of urethane carbonyl and ester carbonyl region of polyester polyurethane resin.—C■Ointnot formed hydrogen bonds,and—C■Oextpart formed hydrogen bonds,the degree of—C■Oexthydrogen bond increases from 5%to 9%with the increase of the chain extension ratio of small molecule diol.When the hard segment content of polyester polyurethane resin was about 20%,free urethane carbonyl and ester carbonyl were mainly 60%.With the increase of urethane/urea,under the combined influence of the asymmetric structure of 2,4-TDI,the degree of H-bonded urethane carbonyl and urea carbonyl in the polyester-PU decreased,free urethane carbonyl,ester carbonyl and urea carbonyl increased,which indicated that the microphase seperation of the polyester-PU was weakened,the mixing of soft and hard segments was enhanced.The degree of H-bonded urea carbonyl overall was a small proportion 6%.P was 0.25,the degree of H-bonded urethane carbonyl in P-PU was larger,and then decreased.