两种固化剂对PBT弹性体力学性能的影响

To investigate the influence of chemical structure of curing agent on the mechanical property of 3, 3-diazidomethyloxetane-tetrahydrofuran copolyethers (PBT) elastomer, N100, the addition product of hexamethylene diisocyanate (HDI) and H₂O, and the mixture of trimethylolpropane and HDI (TMP/HDI), were used as curing agent respectively to produce two type of cross-linked PBT elastomer. Results show that in the same chemical crosslinking network, the tensile strength, tensile strain at break and initial modulus of PBT-N100 elastomer S0 are (0.983±0.03) MPa, (110±7) % and (1.80±0.02) MPa, respectively, while the PBT-TMP/HDI elastomer S4 are (1.43±0.08) MPa, (336±6) % and (1.26±0.01) MPa, respectively. The tensile modulus of elastomer S0 is higher than that of elastomer S4, as its elongation at break and tensile strength poorer than that of S4. Low field NMR reveals that the physical crosslinking strength of PBT-N100 elastomer S0 network chains is higher than that of S4. The strong hydrogen bonding between urea carbonyl group and amidogen in N100 enhances the physical interaction among PBT elastomer network chains, resulting in the tensile modulus of elastomer S0 higher than that of S4, while its elongation at break lower than that of S4.