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The degree of crystallinity is estimated by different analytical methods and it typically ranges between 10 and 80%, with crystallized polymers often called "semi-crystalline". The properties of semi-crystalline polymers are determined not only by the degree of crystallinity, but also by the size and orientation of the molecular chains.
Polyaryletherketone (PAEK) is a family of semi-crystalline thermoplastics with high-temperature stability and high mechanical strength whose molecular backbone contains alternately ketone (R-CO-R) and ether groups (R-O-R). The linking group R between the functional groups consists of a 1,4-substituted aryl group. [1]
Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer. The semicrystalline material might appear transparent (particle size less than 500 nm ) or opaque and white (particle size up to a few micrometers ) depending on its crystal structure and ...
The development of plastics has evolved from the use of naturally plastic materials (e.g., gums and shellac) to the use of the chemical modification of those materials (e.g., natural rubber, cellulose, collagen, and milk proteins), and finally to completely synthetic plastics (e.g., bakelite, epoxy, and PVC).
All polymers (amorphous or semi-crystalline) go through glass transitions. The glass-transition temperature ( T g ) is a crucial physical parameter for polymer manufacturing, processing, and use. Below T g , molecular motions are frozen and polymers are brittle and glassy.
PB-1 is a high molecular weight, linear, isotactic, and semi-crystalline polymer. PB-1 combines typical characteristics of conventional polyolefins with certain properties of technical polymers. PB-1, when applied as a pure or reinforced resin , can replace materials like metal, rubber and engineering polymers.
In polymer physics, spherulites (from Greek sphaira = ball and lithos = stone) are spherical semicrystalline regions inside non-branched linear polymers. Their formation is associated with crystallization of polymers from the melt and is controlled by several parameters such as the number of nucleation sites, structure of the polymer molecules, cooling rate, etc. Depending on those parameters ...
Although the two phases are chemically equivalent, semi-crystalline polymers can be described both quantitatively and qualitatively as composite materials. The crystalline portion has a higher elastic modulus and provides reinforcement for the less stiff, amorphous phase.