Table 12.4 Polymers of Commercial Importance Synthesis of Polyurethane氨纶，聚氨酯 H H N十c=0+o- OH H the urethane groups (-NH-(C-O)-O-)link the molecular units. Polyurethane fabric
Table 12.4 Polymers of Commercial Importance / / Synthesis of Polyurethane 氨纶,聚氨酯 the urethane groups ( –NH–(C=O)–O– ) link the molecular units. Polyurethane fabric
Polymer Chemical Structure Linear 线形 无规支化 梳形支化 星形支化 Random branched Comb branched Star-type branched Cross-linking 交联网络
Polymer Chemical Structure Linear 线形 Cross-linking 交联网络 Star-type branched Random Comb branched branched
Properties of Polymers Are they made from Polyethylene? 聚乙烯 HDPE LOPE-LOW DENSITY POLYETHYLENE E栏别OM IOKTHUSAC1 MAPPUCAT2N性 LDPE
Properties of Polymers 聚乙烯
Properties of Polymers These branches inhibit the formation of Less branching and higher crystalline regions,reduce the density of degree of crystallinity. 结晶的 materials 结晶度 Branched Linear Low density PE High density PE LDPE: HDPE: Molar Molar mass: mass: 104 ~106 The properties of PE can be "tuned"by varying the average length, crystallinity,and branching of the chains,making it a versatile material
Properties of Polymers These branches inhibit the formation of crystalline regions, reduce the density of materials Less branching and higher degree of crystallinity. Branched Linear Low density PE High density PE 结晶的 结晶度 LDPE: Molar mass: ~ 10 4 HDPE: Molar mass: ~ 10 6 The properties of PE can be “tuned” by varying the average length, crystallinity, and branching of the chains, making it a versatile materials
Polymer Classifications ·Crystalline:结晶的 - Periodic 3-D,repeating array of molecules 。Amorphous:无定型的 -Literally“without structure” No repeating array 。·Semi-crystalline:半结晶的 Structure containing regions of both crystalline and amorphous molecular arrangements
Polymer Classifications Thermoplastics 结晶的 无定型的 Thermosets 半结晶的