Study on the Preparation and Curing Shrinkage of Liquid Optical Clear Adhesive

紫外光（UV）固化的液态光学胶（LOCA）具有优异的性能而且应用广泛，但固化过程中出现的体积收缩现象，严重影响其粘接强度和产品外观。故随着环保和工业需求的不断提升，低有机物挥发（VOC）含量和低固化收缩率的液态光学胶成为了研究重点。 本文以预聚物、活性稀释剂和光引发剂为研究对象进行了系统地研究，研究了聚氨酯丙烯酸酯（PUA）、环氧丙烯酸酯（EPA）、液态聚丁二烯、聚丁二烯丙烯酸酯、聚醚丙烯酸酯等多种预聚物的固化收缩率和共混互配后的固化效果，发现聚醚丙烯酸酯与环氧丙烯酸酯（EPA）共混互配后效果最好。研究了活性稀释剂的种类、用量、光引发剂的用量、光固化的类型等诸多因素对固化收缩率的影响，发现了...UV-curing of liquid optical clear adhesive has excellent properties and is widely used, but the volume shrinkage has a serious effect on the adhesive strength and appearance of the product during UV-curing. Liquid optical clear adhesive(LOCA) of low VOC and low curing shrinkage is becoming the focus of research, with the rising of environmental protection and industrial demand. In this paper, a s...学位：理学硕士院系专业：材料学院_高分子化学与物理学号：2072011115006

新型压疮防护系统对压疮高危风险病人的防护作用的研究

[目的]探讨新型压疮防护系统对压疮高风险病人的压疮预防性作用。[方法]选取吉林省人民医院2015年2月—2017年2月具有压疮高风险（Braden评分〈12分）的住院病人126例,首先给予常规压疮预防护理45例作为对照组,后81例病人给予新型压疮防护系统作为预防性的措施为实验组,通过观察两组的皮肤情况,统计病人的压疮发生率和评价病人的舒适度。[结果]实验组病人住院第2天、住院第7天压疮发生率低于对照组,差异有统计学意义。[结论]新型压疮防护系统能降低压疮高风险病人的压疮发生率。吉林省卫生计生委课题,编号：2015SZC1

Studies on Curing Shrinkage of Liquid Optical Clear Adhesive

紫外光固化的液态光学胶固化过程中出现的体积收缩现象,严重影响其黏接强度和产品外观.系统研究了液态光学胶预聚物的种类、活性稀释剂的种类和用量、光引发剂的用量、光固化的类型等诸多因素对固化收缩率的影响.研究发现,以聚乙二醇二丙烯酸酯作为预聚物可明显降低固化收缩率.当添加的活性稀释剂官能度相同时,胶黏剂的固化收缩率随活性稀释剂相对分子质量的增加而减小;当活性稀释剂相对分子质量相近时,官能度增加,固化收缩率随之增大.而光引发剂的用量则对固化收缩率无明显影响.阳离子型胶黏剂的固化收缩率比自由基型的小,但硬度和黏接强度较低;而混杂型的固化收缩率则介于二者之间.The volume shrinkage during UV-curing of liquid optical clear adhesives(LOCA)had a serious effect on the adhesive strength and appearance of the product.In this paper,the effect of different factors,including types of active diluents,amounts of active diluents and photo-initiators,and UV-curing types,on the volume shrinkage for LOCA was systematically investigated.Based on the experiment,polyethylene glycol diacrylate as the prepolymer could significantly reduce the shrinkage.With the same functionality of the added active diluents,the shrinkage decreased when the molecular weights of the active diluents increased.When the molecular weights of active diluents were similar,the shrinkage increased with the increase of the functionality.The amount of photo-initiators had no significant effect on shrinkage.The shrinkage of cationic adhesives was smaller than that of radical adhesives,but the hardness and adhesion strength were relatively lower.The shrinkage of hybrid adhesives was in between in general

The changes in cooperation among strangers in China: A cross-temporal meta-analysis of social dilemmas (1999~2019)

陌生人间的合作行为对于解决社会公共问题,应对世界百年未有之大变局意义重大。本研究采用横断历史元分析方法,基于1999～2019年间开展的254项使用社会困境范式测量我国陌生人间合作行为的研究(共302个合作率,29249名被试,平均年龄：18～28岁),探讨了中国社会中合作行为的变迁及一些社会发展指标在其中的解释作用,并比较中美两国的合作行为变迁趋势。结果表明,中国人的合作行为水平随时间而上升,一些社会发展指标(人均国内生产总值、城市化率、高等教育水平、互联网普及率等)可能是其上升的社会变迁基础。中美两国合作行为表现出相似的上升趋势,但中国的在更短时间内有更大上升幅度。研究结果对提振民众信心具有重要意义。</p

Study on Activity Persistance of Polyester Polymercaptan Curing Agent

对比了聚醚型聚硫醇和2种聚酯型聚硫醇的活性寿命的差异.通过红外光谱、1 H-nMr和凝胶时间的测试表征聚硫醇的活性寿命.结果表明,以叔胺为促进剂时,以β-巯基丙酸为原料制备得到的聚酯型聚硫醇P(SH)6和聚醚型聚硫醇P(SH)3固化剂都有良好的活性寿命;而以α-巯基乙酸为原料制备得到的聚酯型聚硫醇P(SH)4固化剂存在活性下降的问题,2个月后完全失活.通过红外光谱、1 H-nMr表征活性下降前后其基团的变化提出了可能导致其活性下降的机理及解决的方法.The lifetime differences of polyether polymercaptans and two kinds of polyester polymercaptans were compared in this paper.The lifetime of polymercaptans curing agents was characterized by FT-IR,1 H-NMR and gelation time.The results revealed that polyester polymercaptans P(SH)6and polyether polymercaptans P(SH)3composed of 3-mercaptopropionic acid showed a long lifetime when using trialkylamine as accelerator,while polyester polymercaptans P(SH)4composed of 2-mercaptopropionic acid showed a decrease in curing activity and deactivated within two months.Possible mechanism of the decrease in curing activity was proposed based on the investigation of group changes during the deactivation by FT-IR and 1 H-NMR