There are many types of plastics, and even if we focus on PP (polypropylene)
Even if we focus on PP (polypropylene), it can be divided into three types: homopolymer, random copolymer, and block copolymer.
Homopolymer is said to have excellent rigidity and heat resistance.
How is the strength of such resins determined?
Taking the tensile test of molded plastic products as an example
At room temperature, plastic is composed of intertwined molecular chains.
When a tensile load is applied in this state
Entangled molecules are gradually disentangled. When the entanglement is completely lost, rupture (fracture) occurs.
In other words, a material that is difficult to break (a material with high strength) can be said to have a strong entanglement.
Recycled materials are said to have low physical properties, but this is thought to be due to the fact that they are molded in a state where the entanglement of molecules has been loosened.
It is possible that the physical properties of recycled materials can be restored to the same level as those of virgin materials by adding a process that increases molecular entanglement.
Sanko Gosei has been a member of a NEDO project on resin molding recycling since fiscal year 2019, and is conducting research on the relationship between molding conditions and material properties.
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