How can i harden the recycled plastics? Any idea?

Answer 1

The question asks more questions.

Plastics is a generic term. Which polymer? Is it a thermoset or thermoplastic.

As you harden many plastics they become brittle. Is this a problem? Often when the term "harden" is used, the actual meaning is quite different. It may mean less brittle, more flexible, greater tensile strength, etc. What do you wish to do?

Sometimes, if you are dealing with a specific polymer (polyethylene for example), you can mix different proportions of specific MW and achieve the properties you want.

Mixing differrent but similar polymers may also work to achieve what you want, but sometimes the mixing just does not do the job on its own.

Recycled plastics are of an uncertain composition - and the compositon varies as you use them making it even more difficult to achieve uniform result. To make matters worse, recycled plastic can be contaminated by the contentes they had contained in their original use and this can really gum up the works.

I strongly urge you to be more specific in your feed stock and end use desire so greater info can be provided.