To compare the suitable working conditions of polypropylene(PP)and polycaprolactam(PA6)materials in actual use in automobiles,the effects of different temperature aging and different reagents on the mechanical propert...To compare the suitable working conditions of polypropylene(PP)and polycaprolactam(PA6)materials in actual use in automobiles,the effects of different temperature aging and different reagents on the mechanical properties of the two materials,such as tensile,bending,compression,and impact were studied.The results indicate that the short⁃term low⁃temperature environment had no much effect on the mechanical properties of PP and PA6.After long⁃term thermal aging at 80℃,the strength of PP and PA6 increased while their toughness decreased.After short⁃term thermal aging at 120℃,PP strength decreases and toughness increases,while PA6 strength increases and toughness decreases.The soaking of glass water and car shampoo had no much effect on the mechanical properties of PP,but had a significant impact on the mechanical properties of PA6.With the increase of soaking time,the strength of PA6 significantly decreases and the toughness significantly increases.The soaking of 95#gasoline had no much effect on the mechanical properties of PA6,but has a significant impact on the mechanical properties of PP.After 720 h of soaking,the retention rates of the tensile strength,bending strength,and compressive strength of PP were all less than 80%,while the retention rate of the impact strength of the cantilever beam was 160.4%.展开更多
Three polycaprolactam samples modified by 0.05—0.50% polyphenylquinoxaline(PPQ)by weight were prepared.Their structure and mechanical properties were characterized by FT-IR, SEM, density, tensile, impact, DTAand visc...Three polycaprolactam samples modified by 0.05—0.50% polyphenylquinoxaline(PPQ)by weight were prepared.Their structure and mechanical properties were characterized by FT-IR, SEM, density, tensile, impact, DTAand visco-elastic method, PPQ induced the formation of 'crystal grains' distributed evenly over nylon spherulites in modified samples, which were observed for the first time, and strengthened modified samples. Modified nylons had higher crystallinities, higher T_g, more nearly perfect spherulites than MC nylon itself, and showed typical reinforcing effect on mechanical properties.展开更多
Three polycaprolactam samples modified by 0.05—0.50% polybenzimidazole （PBI） by weight were prepared. Their structure and mechanical properties were characterized by means of FT-IR, SEM, DTA, density tensile, impac...Three polycaprolactam samples modified by 0.05—0.50% polybenzimidazole （PBI） by weight were prepared. Their structure and mechanical properties were characterized by means of FT-IR, SEM, DTA, density tensile, impact and viscoelastic method. PBI delayed the superimposed polymerization-crystallization process of the activated anionic polymerization of caprolactam. The monomer casting （MC） nylons modified by PBI had lower crystallinities, lower T;and more nearly perfect spherulites than MC nylon itself, and showed a typical toughening effect.展开更多
The insertion of 1,1-bis (1′-naphthyl) ethylene monomer unit into the active polystyrene chain end greatly decreased the reactivity of the active chain end to the carbonyl group, and allowed the polymeric chain end t...The insertion of 1,1-bis (1′-naphthyl) ethylene monomer unit into the active polystyrene chain end greatly decreased the reactivity of the active chain end to the carbonyl group, and allowed the polymeric chain end to react only with the double bond in N-methacryloyl caprolactam, resulting in N-acylcaprolactam functionalized polystyrene in 100% conversion. New diblock copolymer of polystyrene with polycaprolactam was synthesized by direct reaction of the functionalized polymer with caprolactam without adding additional alkali metal or their caprolactam salts.展开更多
利用聚酰胺吸附与NaNO2-A l(NO3)3显色相结合测定山楂总黄酮,通过对比色条件的优化,获得快速测定山楂总黄酮含量的方法。结果表明,该测定方法基本上消除了杂质的干扰,精密度高,在30 m in内显色稳定,重现性较好,平均加样回收率为99.9%,RS...利用聚酰胺吸附与NaNO2-A l(NO3)3显色相结合测定山楂总黄酮,通过对比色条件的优化,获得快速测定山楂总黄酮含量的方法。结果表明,该测定方法基本上消除了杂质的干扰,精密度高,在30 m in内显色稳定,重现性较好,平均加样回收率为99.9%,RSD=1.06%。展开更多
文摘To compare the suitable working conditions of polypropylene(PP)and polycaprolactam(PA6)materials in actual use in automobiles,the effects of different temperature aging and different reagents on the mechanical properties of the two materials,such as tensile,bending,compression,and impact were studied.The results indicate that the short⁃term low⁃temperature environment had no much effect on the mechanical properties of PP and PA6.After long⁃term thermal aging at 80℃,the strength of PP and PA6 increased while their toughness decreased.After short⁃term thermal aging at 120℃,PP strength decreases and toughness increases,while PA6 strength increases and toughness decreases.The soaking of glass water and car shampoo had no much effect on the mechanical properties of PP,but had a significant impact on the mechanical properties of PA6.With the increase of soaking time,the strength of PA6 significantly decreases and the toughness significantly increases.The soaking of 95#gasoline had no much effect on the mechanical properties of PA6,but has a significant impact on the mechanical properties of PP.After 720 h of soaking,the retention rates of the tensile strength,bending strength,and compressive strength of PP were all less than 80%,while the retention rate of the impact strength of the cantilever beam was 160.4%.
基金Project supported by the National Natural Science Foundation of China.
文摘Three polycaprolactam samples modified by 0.05—0.50% polyphenylquinoxaline(PPQ)by weight were prepared.Their structure and mechanical properties were characterized by FT-IR, SEM, density, tensile, impact, DTAand visco-elastic method, PPQ induced the formation of 'crystal grains' distributed evenly over nylon spherulites in modified samples, which were observed for the first time, and strengthened modified samples. Modified nylons had higher crystallinities, higher T_g, more nearly perfect spherulites than MC nylon itself, and showed typical reinforcing effect on mechanical properties.
基金Project supported by the National Natural Science Foundation of China,
文摘Three polycaprolactam samples modified by 0.05—0.50% polybenzimidazole （PBI） by weight were prepared. Their structure and mechanical properties were characterized by means of FT-IR, SEM, DTA, density tensile, impact and viscoelastic method. PBI delayed the superimposed polymerization-crystallization process of the activated anionic polymerization of caprolactam. The monomer casting （MC） nylons modified by PBI had lower crystallinities, lower T;and more nearly perfect spherulites than MC nylon itself, and showed a typical toughening effect.
文摘The insertion of 1,1-bis (1′-naphthyl) ethylene monomer unit into the active polystyrene chain end greatly decreased the reactivity of the active chain end to the carbonyl group, and allowed the polymeric chain end to react only with the double bond in N-methacryloyl caprolactam, resulting in N-acylcaprolactam functionalized polystyrene in 100% conversion. New diblock copolymer of polystyrene with polycaprolactam was synthesized by direct reaction of the functionalized polymer with caprolactam without adding additional alkali metal or their caprolactam salts.
