An investigation on the polymer’s behavior in sealants, influence of rheological factors’ changes and quality improvement of its problems

سال انتشار: 1394
نوع سند: مقاله کنفرانسی
زبان: انگلیسی
مشاهده: 540

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شناسه ملی سند علمی:

ICCC06_177

تاریخ نمایه سازی: 25 بهمن 1394

چکیده مقاله:

This study describes the types of sealers and specially the sealers that are used in automotive and the conventional of those sealers that based on plastisols & methods of production and their material composition. In all of forming process of polymers, shear stress effects on the melt. Shear stress is a function from shear rate which is forced to the molten polymer. Generally, according to the essential properties of most of molten polymers, increasing of the shear rate leads to decreasing the shear viscosity. The reason is resistance of the molten polymers and polymeric bonds which are twisted together like coils, against the little stress in low shear rate. While with increasing the stress and shear rates, gradually the coil like state of the polymeric bonds will open which is oriented in the direction of the shear flow’s force and will move with the mentioned flow easily. Different factors like length of bonds or average molecular weight and molecular weight distribution will affect over the changes of the behavior of molten polymer viscosity, against the changes of the shear rate. In the low shear rates, changes of the shear viscosity against the shear rate is miner and almost equal zero, but sudden drop of molten viscosity will start, with increasing the shear rate from on special point. Specially in low shear rates, increasing of the average molecular weight causes increasing the molten viscosity. Increasing the length of bonds cause more entanglement that result in more resistance of them against the shear flow. It is possible that little differences of average molecular weight in the high shear rates could not be considered according to arrangement of the bonds and ease of their movement in the d irection of the shear flow. For the samples with equal average molecular weight, when the distribution of molecular we ight is wider, starting of the molten viscosity’s drop in the low shear rates will happen.

کلیدواژه ها:

plastisols - Sealer- Shear rate – Viscosity – Mole cular weight

نویسندگان

N. Mazreati Taaj Abadi

Islamic Azad University, Science and Research Branch, Tehran, Iran

Sh. Kianimehr

Paint Shop Management, IRAN KHODRO CO, Tehran , Iran

M. Mehranpour

Islamic Azad University, Science and Research Branch, Tehran, Iran

M. Mirfakhrae

Paint Shop Management, IRAN KHODRO CO, Tehran , Iran

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  • I.Nass and A.Heiberger, _ Encyclopedia of PVC, Resin Manufacture& Properties, ...
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