【作者】 梁栋；

【导师】 王小萍；

【作者基本信息】 华南理工大学 ， 材料学， 2020， 硕士

【摘要】 传统的橡胶是以共价键的方式来构建交联网络结构,制备的橡胶材料难以回收再利用,对环境造成黑色污染的同时,严重威胁着人们的健康及生态平衡。如果橡胶材料在废弃之后能通过加工使其重新恢复到原来的使用性能,那么就可以充分发挥材料的使用价值。赋予橡胶热可逆结构是实现橡胶热可逆重复加工的有效方法。本研究通过制备带有氮氧自由基的热可逆交联剂代替传统交联剂直接交联橡胶,从而赋予橡胶热可逆重复加工的能力。本文首先合成了含有氮氧自由基的热可逆交联剂双(2,2,6,6-四甲基哌啶氧基)-(4-甲基-1,3-亚苯基)二氨基甲酸酯(DTEMPO),并将其应用于热可逆丁苯橡胶(DSBR)的制备,通过红外光谱、核磁共振氢谱、和电子自旋共振分析等测试手段表征DTEMPO的结构及证明了DSBR在交联过程中主要是氮氧自由基与橡胶分子链上碳碳双键的反应,其热可逆机理主要是交联点烷氧基胺在高温时发生裂解产生碳自由基与氮氧自由基,在低温时重新键合形成烷氧基胺结构。通过与单官能度交联剂反应的橡胶对比发现,DTEMPO具有交联丁苯橡胶的作用。弹性模量分析表明,DSBR的弹性模量在高温时下降低温时上升。通过在二甲苯中的高温溶胀实验表明,DSBR在高温中将发生解交联。通过拉伸试验表明随着DTEMPO用量的增大,DSBR的拉伸强度先增大后减小,当DTEMPO用量为10 phr时拉伸强度达到7.46 MPa,断裂伸长率达到1057%。且与硫磺交联的丁苯橡胶相比,DSBR具有较高力学强度的同时还具有优异的重复加工性能。本文还在DTEMPO的基础上制备了另一种热可逆交联剂4-甲基-1,3-亚苯基-双(乙基氨甲酰基)双(2,2,6,6-四甲基哌啶氧基)二苯乙基苯甲酸酯(STEMPO),并应用于热可逆顺丁橡胶(TBR)的制备。利用红外光谱和电子自旋共振等测试手段证明TBR在热可逆过程中也同样是交联点烷氧基胺高温时发生裂解产生碳自由基与氮氧自由基,低温时重新键合形成烷氧基胺结构。通过拉伸测试表明当STEMPO用量为15 phr时TBR拉伸强度为4.29 MPa、断裂伸长率为518%,且TBR也具有较好的重复加工性能。加入白炭黑填充TBR制备复合材料发现,白炭黑的加入可对TBR产生补强作用,当白炭黑用量为30 phr时,TBR的拉伸强度达到9.08 MPa,断裂伸长率达到322%,且白炭黑填充的TBR同样具有较好的重复加工能力。更多还原

【Abstract】 The traditional rubber was vulcanizing with covalent bond,leading to an irreversible network structure.The rubber material was difficult to recycle and reuse,which caused black pollution to the environment and seriously threat to people’s health.If the rubber material could be processed to restore its original performance after being abandoned,then it could give full play to the use value of the material.Endowing rubber with thermo reversible structure is an effective method to realize the repeated processing of rubber.In this study,the rubber was directly cross-linked by the preparation of a thermo reversible crosslinker with nitroxides instead of the traditional crosslinker,so that the rubber could be thermoreversible and reprocessed.In this study,DTEMPO was synthesized and applied to the preparation of DSBR.The structure and crosslinking mechanism of DSBR were characterized by Infrared spectroscopy(FTIR),nuclear magnetic resonance hydrogen spectrum(~1H NMR),differential scanning calorimetry(DSC)and electron spin resonance(ESR).It was proved that the reaction of nitroxides was react with carbon-carbon double bond on rubber molecular chain in the process of crosslinking.In the process of thermal reversibility,alkoxyamines were broken down at high temperature to produce carbon radicals and nitroxides,and rebonded at low temperature.It was found that DTEMPO has the function of crosslinking styrene butadiene rubber by comparing with the rubber reacted by monofunctional crosslinker.The modulus analysis showed that the modulus of DSBR decreased at high temperature and increased at low temperature.The results of swelling experiments in xylene showed that DSBR would be de-crosslinked at high temperature.The tensile test showed that with the increase of DTEMPO content,the mechanical strength of DSBR increased first and then decreased.When DTEMPO content was 10phr,the tensile strength reached 7.46MPa,and the elongation at break reached 1057%.Compared with the irreversible sulfur crosslinked SBR,DSBR had higher mechanical strength and excellent reprocessing performance.Another reversible crosslinker STEMPO was prepared and applied to the preparation of TBR.It was proved by FTIR and ESR that the cleavage of alkoxyamines at high temperature resulted in the formation of carbon radicals and nitroxides,and the formation of alkoxyamine structure at low temperature during the repeated processing of TBR.The tensile test showed that the tensile strength of TBR was 4.29MPa and the elongation at break was 518%when the amount of STEMPO was 15phr.TBR also exhibited good reprocessing performance.The results show that the addition of silica can strengthened TBR.When the content of silica was30 phr,the tensile strength of TBR reached 9.08 MPa and the elongation at break reached 322%.Moreover,TBR filled with silica also had good reprocessing ability.更多还原