| The preparation of transparent nylon is the hot area of research on polymericmaterials for quite a long time. The study reports about transparent nylon are moreand more in China, the reason for which is that the properties of many transparentmaterials can’t meet the need of production and use. At present, China’s consumptionof transparent nylon is very large. Most of the products which are very expensive areimported from abroad. With the industrial-scale production of cycloaliphatic diamineand cycloaliphatic dibasic acid with rings, also in order to solve the problem oftransparent nylon’s long-term dependence on imports, the synthesis of new kinds oftransparent nylon with these monomers has great realistic significance.In this article, two cycloaliphatic diamines (bis(4-amino-3-methyl cyclohexyl)methane (MACM) and bis (4-aminocyclohexyl) methane (PACM)), decane diamineand dicarboxylic acids which have long straight carbon chains were choosed asreactive monomers. Aliphatic transparent nylon in this article was successfullysynthesized in two different ways. One is blending. At first, two better formulasNo.1(nylon PACM12/1012) and No.2(nylon MACM12/1012) were got from smallexperiments in tubes by means of melt polycondensation. After expandingexperiments performed in a big reactor, they were blended with a kind ofsemi-crystalline nylon1012, from which two preferable formulas No.3and No.4wereobtained. Then their optical properties and machanical properties were tested. Theother way is using vacuumizing in later stage reaction to improve the degree ofcrystallinity, from which another two better formulas No.5(nylon PACM10) andNo.6(nylon MACM10) were obtained. Then their optical properties and machanicalproperties were also tested. Then we characterized their aggregation structure andstudied their thermal properties and rheological behavior. The conclusions we havegot are listed below:(1) The tensile strength, bending strength, notched impact strength andtransmittance of No.3are separately49.3MPa,38.1MPa,8.1kJ/m2and85.3%, whilethose of No.4are separately49.6MPa,36.8MPa,13.8kJ/m2and87.6%. The tensile strength, bending strength, notched impact strength and transmittance of No.5areseparately61.5MPa,48.6MPa,11.9kJ/m2and92.0%, while those of No.6areseparately64.8MPa,55.2MPa,13.3kJ/m2and90.7%. The data above shows theirexcellent mechanical properties and optical properties, which can meet the demandsof transparent nylon’s mechanical properties and optical properties in practice.(2) The photographs of X-ray diffusion and polarizing microscope, DSC crystalpatterns all show that nylon No.3and nylon No.4got from the first way aresemicrystalline nylon with lower degree of crystallinity than nylon1012. The degreesof crystallinity of them are separately14.2%,10.5%and45.3%; transparent nylonNo.5and No.6got from the second way are amorphous nylon.(3) The DSC melting curves of No.3and No.4both have a weaker melting peakcompared with nylon1012at about190℃, which show that they are semi-crystallinenylon with lower degree of crystallinity than nylon1012. However, The meltingcurves of No.5and No.6have no melting peaks, which proved that they areamorphous nylon. Their glass transition temperatures got from DSC melting curvesare separately75℃,75℃,87℃and107℃.(4) TG data and images of No.3~No.6transparent nylon tell that theirdecomposition reactions are all one-step reaction. Their thermal degradationactivation energies are calculated by Coats-Redfern integral method, which areseparately454.2kJ/mol,500.4kJ/mol,520.2kJ/mol and529.2kJ/mol. The resultshows their great thermostability.(5) The study on the rheological behavior of four kinds of transparent nylonshows that No.3and No.4obtained from blending have excellent compatibility. Themelt structures of them are relatively stable, having no relationship with temperatures. |
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