What is difference between polypropylene and PVC

PP (isotactic) is a crystalline material that is strong and very light. It is generally opaque or hazy (unless clarifiers are used) and has good resistance to bending (very good to make hinges). It has also higher heat distortion resistance than comparable materials and this it is widely used in medical devices that can be heat sterilized. It is relatively easy to process ans recycle.

PVC is useless by itself as too brittle. It must be used with about 40% phthalate plasticizers (very controversial as they leach and are endocrine disruptors) to make items that are incredibly soft, pliable and clear. Otherwise, a copolymer of vinyl chloride and vinyl acetate can be made. This material is strong but pliable and not transparent and has good abrasion resistance. It can be used to make sanitary tubing, door and windows frame, etc. This material can be also reinforced with carbon black to make it harder but also brittler. One of the main use of this material is/was the fabrication of audio records… Generally, PVC is very hard to recycle. It must be separated from other materials as minimal amounts of it can spoil the recycling of other materials.

                                                                                    PP V.S. PVC

1.PP is short for polypropylene, pvc is short for polyvinyl chloride. 

 2.Polypropylene is one of the most neutral plastics, containing only two elements:  carbon (C) and hydrogen (H). PVC by comparison contains about 30% by weight, of the element Chlorine (Cl) in its basic structure. It is well documented that chlorine, like all halogens, is a dangerous substance in the environment. 

3.When PVC is incinerated or present in accidental fires it produces toxic byproducts such as dioxins, chlorocarbons and hydrochloric acid. Complete combustion of PP, on the other hand, will generate only carbon dioxide and water.

 4.PVC is intrinsically heat unstable and can even decompose during processing. PP is much more tolerant to heat; even under extreme conditions it will only decompose to lower molecular weight paraffins, which are elementally compatible with the base material.