抄録
The breaking processes of monofilaments of nylon6 and polyvinylidene fluoride were studied under elongation. The load was measured by a piezoelectric element and fracture surfaces were observed by an electron microscope. The breaking of nylon started from scratches on surfaces, and had three processes, i.e., a crack formation and a lowspeed growth, a high speed growth, the complex growth accompanied with other fractures. Each process had a cheracteristic fracture morphology and was partitioned by two border lines. The crack growth speeds of each process were 20, 41, 69m/s, respectively and the average was 33m/s. The heat by crack growth was culculated 150°C from the average speed and fracture surfaces were estimated to become 260°C . This temperature was consisted with the melted morphologies. The breaking of polyvinylidene fluoride started from inside and had three processes, i.e., the formation of a cohered molecular bundle and its cutting, a low speed growth, a high speed growth. The bundle was composed with molecular chains of 108. The crack growth speeds were 22m/s at low, 36m/s at high and 29m/s at the avrage. Areas were partitioned by a border line and had different morphologies respectively.
