Polymer blend (PB): Mixture of at least two macromolecular substances, polymers or copolymers, in which the ingredient content is above 2 wt%.
The advantages of blending fall into two categories:
A. Blending may improve resin or product performance by:
1. Producing materials having a full set of the desired properties at lowest cost.
2. Extending the engineering resins’ performance by incorporation of less expensive polymers.
3. Improvement of specific properties.
? Brittleness : Toughening brittle polymers, thus eliminating the need to use low molecular weight additives
(e.g., plasticizer in the flexible PVC formulations(
? Modulus & Dimensional Stability: Blending with more rigid and more heat resistant resin
? Improve Solvent and Chemical Resistance: Incorporation of semicrystalline polymer into an amorphous resin
(e.g., blends of PC with PEST)
?Improve Flame Resistance :Incorporation of non-flammable resin into a flammable one (e.g., styrenics or acrylics with PVC)
? Permanently Anti-Static blends :Blends with polymers having either –OH or –SH functionality (e.g., ethylene oxide- coepichlorohydrin with ABS/PC blend).
?Biodegradability: Incorporation of a biodegradable resin
?Blending makes it possible to produce integrated multi-layer structures
4. Providing means for recycling of industrial and/or municipal plastics waste.
5. The blending technology makes it possible to rebuild high molecular weights of partially degraded polymers, thus to produce high performance articles from the plastics waste.
B. Blending may lead to improved processability:
1. Process the high Tg resin at temperatures well below the thermal degradation limit: Incorporation of a miscible resin with a lower glass transition temperature (Tg) (e.g., PS/PPE blends).
2. Reduce pressure drop across dies or runners, thereby increasing productivity: Incorporation of an immiscible, low viscosity resin (e.g., LCP/PEEK blends).
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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