Question

what are the differences between crystalline & amorphous polymers?

Answer 1

well there is often used term semi crystalline polymer cause there is always some portion of polymer which is amorphous, for example a polymer with 50 % crystalline phase is considered crystalline polymer etc.
but difference is that semi crystalline polymers have melting point where amorphous have only glass transition. that data can be seen in DSC or DMTA analysis where you get one more peak in crystalline polymers which is missing in amorphous polymers... now what physical expectation you can get from crystalline polymer you will ask, well they are more rigid but are more difficult to process in extrusion machines etc... if you want more just say cause now you hit my spot cause im about to become master in chemistry (section materials - polymers, glass, ceramics, and non-metal inorganic compounds or example concrete...)