Synthesise of Polythioether and Heat Resistant Property of Polythioether Sealants
Polythioether sealants are considered as new generational aeronautical sealants.The relationship between main chain structure of polythioether and their high temperature properties were studied,in order to use Polythioether sealants in higher temperature condation.First,by changing molecular structure,the feasibility of forming certain molecular weight of polythioethers was studied.Experiment show that most terminal dienes can react with dithiol generating certain molecular polythioethers.Then,analysis show that the linear polythioethers owning high degree of molecular reqularity usually have rather low glass transition temperature(Tg),below-50℃,however,those polythioethers are very easily to crystalize,for example,reaction products of Diethylene glycol divinyl ether(DGDE)between 1,2-Ethanedithiol or Bis(2-mercaptoethyl)sulfide and resultant of 1,4-Bis(vinyloxy)-butane reacting with 2,2-(ethylenedioxy)diethanethiol(DMDO).They are solid at room temperature.To some linear polythioethers,which have lower degree of molecular regularity than preceding three type of polythioethers,i.e.reaction products of 1,6-Hexanedithiol or 2,2-oxydiethanethiol between DGDE,employing differential scanning calorimetry(DSC)the ability of their crystallization can be proved,however,they are still liquid in the room temperature.Therefore they can be used as raw rubber.Comparing with polythioether synthesized by DGDE and DMDO,if main chain of polythioether contains benzene ring,5%weight loss temperatures will be improved,however,Tg will increase a lot,which cannot allow them to be used at low temperature.At last,using those polythioethers which are liquid at room temperature as raw rubber and Manganese Dioxide(MnO2)as curing agent,prepare kinds of sealants.The result shows that polythioether sealant prepared by reaction product of 1,6-Hexanedithiol and DGDE has the highest tensile strength,which is 5.84MPa.If the main chains of polythioethers contain benzene ring,the tensile strength of sealant made by them will increase.After hot air aging(at 160℃ and 100h),the sealant employing the polythioether synthesized by 2,2-oxydiethanethiol and DGDE has the best thermal stability,the tensile strength only decrease 28%,the tensile strength of sealants containing benzene ring reduce about 65%,using polythioethers having relatively long carbon chain as raw rubber making sealants have the worst thermal stability,their tensile strength decrease about 81%.
polythioether high temperature resistance
Guo Ruiyi Zhang Jianzheng Wu Songhua
AVIC Beijing Institute of Aeronautical Materials,Huanshancun Wenquanzhen haidianqu,Beijing 100095,China
国际会议
2014 Asia-Pacific International Symposium on Aerospace Technology(2014亚太航空航天技术学术会议)
上海
英文
1-7
2014-09-24（万方平台首次上网日期，不代表论文的发表时间）