久久精品久久精品久久精品 I 色在线视频观看 I 亚洲黄色天堂 I 夜夜爱夜夜做夜夜爽 I 国产精品入口网站7777 I 免费一级黄色 I 综合伊人久久在 I 国产成网站18禁止久久影院 I 久久精品免视看国产成人明星 I 日本黄色软件 I 亚洲精品久久在线 I 精品少妇一区二区三区四区五区 I 国产黄视频在线 I 九九九免费观看视频 I 91插插插插插 I 在线国产二区 I 91国产片 I 国产一区二区三区视频在线 I 亚洲精品中文字幕无码蜜桃 I 精品亚洲精品 I 国产久艹视频 I 国产三级大全 I 精品久久久久国产免费第一页 I a级毛片,黄,免费观看 m I 欧美伦理片免费 I 国产精品狼人久久久久影院 I 日本又白又嫩水又多毛片 I 无码人妻精品中文字幕免费东京热 I 98久久久 I 1314全毛片 I 99亚州精品一区区三区 I 女人av天天堂 I 日本高清久久天堂 I 国产精品天干天干在观线 I ass极品水嫩小美女ass

Polyphenylene sulfide (PPS), a new type of engineering plastic, was only industrialized in the United States in 1973. Let me introduce you to the performance of PPS injection molding, I believe you will be interested in listening.

First, the performance of PPS

1, physical and mechanical properties

PPS is a white, highly crystalline polymer with a density of 1.34. It has excellent mechanical properties, tensile strength and flexural strength superior to PA, PC, PBT, etc. It has extremely high rigidity and creep resistance, but its brittleness is large, and the notched impact strength is lower, lower than PA, PC, PBT. Higher than POM. The addition of glass fiber reinforced has better mechanical properties. PPS is an inert substance and is non-toxic.

2, thermal performance

Since PPS is a crystalline polymer, the highest crystallinity can reach 65%, its crystallization temperature is 127 ° C, the melting point is 286 ° C, the heat distortion temperature is 260 ° C, it decomposes in the air above 430-460 ° C, and the thermal stability far exceeds Engineering plastics such as PA, PBT, and POM have the longest use temperature of thermoplastics up to 220-240 °C. PPS still has good thermal insulation and flame retardancy. Its critical oxygen index is equivalent to that of PVC, up to 47%. No need to add flame retardant, PPS can reach UL94-V0 level.

3, electrical performance

PPS has a symmetrical molecular structure, no polarity and low water absorption, so its electrical insulation is excellent. Compared with other engineering plastics, its dielectric constant is small, and its arc resistance is equivalent to thermosetting plastics. It is high temperature, high humidity, frequency conversion, etc. Under conditions, PPS can also maintain excellent electrical insulation. Conductive PPS composites can be prepared by adding conductive fillers for antistatic and electromagnetic shielding.

4, chemical resistance

Because PPS has high crystallinity, it has excellent chemical resistance. It is insoluble in any organic solvent below 200 °C. In addition to strong oxidizing acid, it can withstand various types of acid, alkali and salt erosion. After long-term immersion by various chemicals, it also maintains high strength, second only to PTFE. PPS also has good weatherability and radiation resistance.

5, processing performance

1) Water absorption

PPS has a low water absorption of only 0.02%.

2) Liquidity

PPS has good fluidity and can process thin-walled products. Its fluidity varies according to the variety and specifications of PPS. Linear PPS has higher fluidity than branched cross-linked PPS. As the temperature increases, the fluidity of the material increases, but If the temperature is too high or the material stays in the barrel for too long, the material will partially crosslink, resulting in lower flow.

3) Crystallinity

PPS is a crystalline polymer whose crystallinity varies depending on the cooling temperature and rate at the time of molding, and the faster the cooling rate, the lower the crystallinity. The degree of crystallinity has a great influence on its strength, heat resistance, weather resistance and dimensional stability. As the degree of crystallinity increases, the thermal transition temperature of the product increases, rigidity, surface finish, surface hard shrinkage rate, etc. increase, and dimensional stability also increases.