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通过溶胀硫化胶的溶剂冰点下降法研究了3种不同促进剂体系天然橡胶硫化胶交联网络结构对力学性能的影响.交联密度研究表明,加入TU或STU硫化胶的交联密度与单独使用CZ促进剂硫化胶的基本一致.溶胀硫化胶溶剂冰点DSC研究结果发现,添加了STU硫化胶的溶剂冰点下降幅度最小,而溶剂冰点下降峰的半峰宽(FWHM)值最大,表明了STU的加入有利于在硫化胶中形成了一个网格尺寸较大和更加不均匀交联键分布的结构.同时,XRD结果表明所有硫化胶的应变诱导结晶总结晶指数相同,即可以忽略其对力学性能的影响.力学性能结果表明添加了STU硫化胶的拉伸强度和断裂伸长达到了最大值,这主要是因为在外力作用下,较大网格尺寸和交联键稀疏区域有利于应力松弛,分散了应力集中,使得橡胶分子链和交联键稠密区的结晶束得到有效取向和松弛,提高了STU硫化胶的拉伸强度和断裂伸长.
The effects of three kinds of different vulcanizates on the mechanical properties of crosslinked natural rubber vulcanizates were studied by means of the freezing point-falling method of solvent vulcanizates.The results of crosslinking density showed that the crosslink density of TU or STU vulcanizates was CZ accelerator vulcanizates are basically the same.Steel vulcanizate solvent freezing point DSC results showed that the addition of the STU vulcanizate solvent freezing point of the minimum decrease, while the solvent freezing point of the peak value of the full width at half maximum (FWHM), indicating that the STU Addition of a structure that favors the formation of a larger and more inhomogeneous cross-link distribution in the vulcanizate.At the same time, the XRD results show that the strain-induced crystallization of all vulcanizates has the same total crystal index, that is, the mechanical properties can be neglected .The results of mechanical properties show that the tensile strength and elongation at break of STU vulcanizate reached the maximum, mainly due to the larger grid size and sparse cross-linking area under the external force, which is conducive to stress relaxation and dispersion The stress concentration causes the crystal strands of the rubber molecular chains and the dense crosslinked domains to be effectively oriented and relaxed, and the tensile strength and breaking of the STU vulcanizate are improved Elongation.