1, polypropylene is a polymer formed by addition polymerization of propylene. It is a white waxy substance with a transparent and light appearance. The chemical formula is (C3H6)n, its density is 0.89 ~ 0.9 1g/cm3, it is flammable, its melting point is 164~ 170℃, it softens at about 155℃, and its service temperature range is-30 ~/kloc.

It can resist the corrosion of acid, alkali, salt solution and various organic solvents below 80℃, and can be decomposed under high temperature and oxidation. Polypropylene is a thermoplastic synthetic resin with excellent properties. It is a colorless and translucent thermoplastic lightweight general plastic with chemical resistance, heat resistance, electrical insulation, high-strength mechanical properties and good wear-resistant processing performance.

2. Protection configuration file refers to a set of security requirements that meet the needs of specific users. It is a kind of TOE and has nothing to do with implementation.

3, positive assumptions, that is, positive assumptions, in the face of problems and interpersonal relationships, to a positive direction. For example, if someone is late for an appointment, I think maybe I arrived early, maybe he deliberately left me some time to prepare, or maybe something happened to him that I couldn't get away from. On the bright side, work and life are much easier and unnecessary troubles are reduced.

4. Percentage point or percentage point, abbreviated as PP, means percentage point. For example, in the government work report (the employment rate of college students reached 74% this year, and it is planned to increase by 5 percentage points next year), that is, the employment rate of college students is planned to increase by 5 percentage points next year (reaching 79%).