Dear Yang-Tao Zhou, chemical resistance of crystalline polymers is much higher than amourphous ones. Polyethylene prepared under high pressure has a degree of crystallinity close to 99%. My Regards

Dear Yang-Tao Zhou ,

Yes, the properties of semicrystalline polymers are determined by the degree of crystallinity and the molecular chains' size and orientation. At room temperatures and normal pressure and temperature, the crystallinity would be between 10 - 85 %.

The crystallization of polymers is intimately related to the molecular chain's partial alignment.

Some polymers at freezing retain the resulting disordered arrangement, so they became amorphous. All properties are going to present some changes.

In a more complex scenario, part of the polymer may order and another part still disordered. Those polymers are not classified as crystalline nor amorphous; they are semicrystalline. Again the properties are related somehow with both regions and, therefore, changed from the original polymer.

Best regards,

WNM

Dear Abdelkader @ Abdelkader BOUAZIZ

Thanks for your answer which is very helpful.

Dear Wagner @ Wagner Da Nova Mussel

Thanks for your answer. As you mentioned that all properties are going to present some changes when the polymer becomes amorphous, could you please give me some instance ?

the degree of crystallinity is a physical property that did not affect the chemical properties but I think the effect is on the response of the matter to the chemical reagent or on the other work it affect on the rate of the reaction

Dear Yang-Tao Zhou ,

I'm sorry for the delay in answering the question, there are many industrial situations where formulators mix two polymers to produce a blend with improved physical properties. As far as pharmaceutical polymers are concerned, they are composed of small molecules. If used in a mixture, an essential concern property would be the miscibility when more than one monomer is present. If two monomers are still in a mixture, the cooling behavior is critical in interpreting the thermogram, for instance.

As mention before In a more complex scenario, part of the polymer may order and another part still disordered. Those polymers are not classified as crystalline nor amorphous; they are semicrystalline, and you can even evaluate the Tg behaviour upon change in crystallinity related or not to the increase In molecular weight.

Best egards,

WNM