The term engineering polymer is applied to a processable resin, capable of being formed to precise and stable dimensions, having high performance at CUT? 100°C, and the tensile strength of ? ? 40 MPa . Five polymer families belong to this category: PA, PEST, PC, POM,
and PPE.
Engineering resins and their blends have been foamed:
1- Using mainly chemical foaming agents, e.g.,hydrazodicarboxylates, benzazimides or 5-phenyltetrazole. However, products of decomposition of these agents (e.g., alcohol, ammonia, water, etc.) were found to hydrolyze PC, PA, PC/ABS, or PEST, reducing the performance of foamed products.
2- For this reason, dihydrooxadiazinones were proposed as the preferred
chemical foaming agents for the engineering resins, their compositions and blends.
Dihydrooxadiazinones
3-Another method for foaming high temperature polymers profits from
thermal instability of polypropylene carbonate (PPCO, MW = 1 to 1000 kg/mol).
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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