Mechanical properties,thermal stability,and flame retardance of novolac‐type phenolic resin blended with poly(dimethylsiloxaneadipamide)

Mechanical properties (flexural strength, flexural modulus, and notched Izod impact strength), thermal stability, and flame retardance of poly(dimethylsiloxane adipamide) (PDMSA)‐toughened novolac type phenolic resin were investigated. Mechanical properties of modified novolac‐type phenolic resin increase with PDMSA contents, because the soft segment of PDMSA absorbs the loads in the network of brittle novolac‐type phenolic resins. TGA results show that the thermal degradation temperatures are higher than 400°C, and the temperature of 10% weight loss increases with increasing the PDMSA content. The char yield increases with novolac‐type phenolic resin content. The morphologies of the fracture surface of the modified novolac‐type phenolic resin were investigated by scanning electron microscopy (SEM). Morphological results agree with those from mechanical properties of the modified novolac‐type phenolic resin. The modified novolac‐type phenolic resin also shows excellent flame retardance that is UL‐94, V‐1, and the limited oxygen index is higher than 35. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 631–637, 2001