Related Legal Terms & Definitions. 1  COMPETENT WITNESS One who is legally qualified to be heard to testify in a cause. 2  RESPECTABLE WITNESS One who is competent to testify in a court of justice. 3  CREDIBLE WITNESS A credible witness is one who is competent to give evidence, and is worthy ofâ¦.
In general, combustibility of polymers depends on their chemical structures. Polymers with more carbon atoms in their macromolecular structure (e.g., PE, PP, PS, PMMA) are more combustible than polymers containing halogen atoms (e.g., PVC, PVDC, PTFE).
I have a general avoidance policy towards plastic, particularly disposable plastic. I seek less toxic alternatives to plastics whenever I can. But I make an extra special effort to avoid certain plastics, including polyvinyl chloride (PVC), also known as vinyl or the #3 plastic.The Center for Health, Environment and Justice (CHEJ) calls PVC  the most toxic plastic for childrenâs health and the environment .. Vinyl is the least recyclable plastic because of the diversity of additives used to make different types of PVC products. 2  In addition, when PVC-products are accidentally mixed with non-chlorine plastics, they contaminate the entire recycling process.