Curing mechanism of TDE-85/MeTHPA epoxy resin modified by polyurethane

Diglycidyl 4,5-epoxy tetrahydro phthalate/methyl tetrahydrophthalic anhydride （TDE-85/MeTHPA） epoxy resin modified by polyurethane （PU） was prepared with 1,4-butanediol （1,4-BDO）, trimethylol propane （TMP） and polyurethane prepolymer synthesized by polypropylene glycol and toluene diisocynate. Chemical reaction and curing mechanism of this system were discussed by incorporating the results of infra spectrum analysis. The results indicate that the epoxy polymeric network I is obtained by the curing reaction between TDE-85 and MeTHPA, while the PU polymeric network II is obtained by the chain-extended and crosslinking reaction between 1,4-BDO, TMP and polyurethane prepolymer（PUP）. The graft chemical bonds are formed between polymer networks I and II that therefore increase the degree of blend and compatibility between epoxy polymer and PU.     

Structural characteristics and properties of polyurethane modified TDE-85/MeTHPA epoxy resin with interpenetrating polymer networks

Diglycidyl-4,5-epoxycyclohexane-1,2-dicarboxylate（TDE-85）/methyl tetrahydrophthalic anhydride （MeTHPA） epoxy resin was modified with polyurethane（PU） and the interpenetrating polymer networks（IPNs） of PU-modified TDE-85/MeTHPA resin were prepared. The structural characteristics and properties of PU-modified TDE-85/MeTHPA resin were investigated by Fourier transform infrared（FTIR） spectrum,emission scanning electron microscopy（SEM） and thermogravimetry（TG）. The results indicate that epoxy polymer network （Ⅰ） and polyurethane polymer network （Ⅱ） of the modified resin can be obtained and the networks （Ⅰ） and （Ⅱ） interpenetrate and tangle highly each other at the phase interface. The micro morphology presents heterogeneous structure. The integrative properties of PU-modified TDE-85/MeTHPA epoxy resin are improved obviously. The PU-modified TDE-85/ MeTHPA resin’s tensile strength reaches 69.39 MPa,the impact strength reaches 23.56 kJ/m,the temperature for the system to lose 1% mass （t1%） is 300 ℃,and that for the system to lose 50% mass （t50%） is 378 ℃. Compared with those of TDE-85/MeTHPA resin,the tensile strength,impact strength,t1% and t50% of the PU-modified resin increases by 48%,115%,30 ℃,11 ℃,respectively. The PU-modified TDE-85/MeTHPA resin has the structure characteristics and properties of interpenetrating polymer networks.     

基坑开挖对邻近管道变形影响的数值模拟研究

随着建筑业高速发展,城市地下空间工程被更广泛应用,基坑开挖的施工必然会对邻近在役的管道造成一定的影响。以南沙某工程区内所进行的第三方基坑施工对邻近管道的保护工程项目为依托,运用Midas GTS有限元软件分析基坑开挖深度、基坑支护结构位移大小形态以及基坑支护结构类型变化时,此基坑开挖对邻近在役管道变形的影响规律,主要得到如下结论：基坑周边管道位移随管道与基坑水平间距的增加呈先增大后减少的规律,基坑支护水平位移越大坑边管道位移越大,基坑倾覆式的位移形态对周边管道影响最大。以实际工程作为依托,本文的研究成果可为深厚软土地区其他类似工程提供参考。     

一种空管自动化系统网络流量监控的设计与实现

提出基于深度包检测的改进方法在空管自动化系统网络流量监控中的应用,最终通过C#设计一套空管自动化系统网络流量监控系统。系统通过串口转换模式接入空管自动化系统,通过相应的协议库引用提高对SNMP协议处理的效率,在实践中有较好的性能体现。     

TDE-85/MeTHPA环氧树脂的聚氨酯改性

采用TDE-85/MeTHPA环氧树脂的聚氨酯(PU)改性,探讨了聚醚二元醇(PPG)分子量大小、聚氨酯预聚体(PUP)加入量等因素对聚氨酯改性TDE-85/MeTHPA树脂体系拉伸强度与冲击强度的影响。研究结果表明,PU改性TDE-85/MeTHPA树脂的力学性能随着PUP加入量的增加先呈上升趋势,达到最大值后又开始下降。合成PUP用的PPG分子量不同时,PU改性TDE-85/MeTHPA树脂的力学性能结果相差比较悬殊,但PU改性TDE-85/MeTHPA树脂的力学性能随PUP加入量的变化趋势是相同的。     

华南滨海深厚软土地层路基处理对邻近燃气管道位移影响分析

针对广州某软土路基处理工程中邻近的市政管线,通过建立管道和地层的三维有限元模型,分析不同施工工况下华南滨海深厚软土地层路基处理对邻近燃气管道位移影响,研究结果表明:（1）采用隔离桩进行保护可较为有效地减小管道的竖向位移,对管道水平位移的影响较小;（2）管道与施工路基的水平距离大于50 m时,可以不采取管道保护措施;（3）管道与施工路基水平距离10～30 m段,采用CFG桩加固的保护措施;水平距离30～40 m段,采用打插塑料排水板+搅拌桩加固的保护措施;水平距离40～50 m段,采用打插塑料排水板的保护措施。由此可知,软基道路施工对既有管线竖向位移的影响较大,水平位移影响较小,施工前应采取一定的保护措施,以期为既有管线的正常使用提供保障。