1. There are many problems in the use of natural rubber stoppers in the packaging of medicines. The presence of proteins, organic and inorganic substances in natural rubber causes adverse allergic reactions to medicines, and natural rubber is non-polar rubber. It can only be resistant to some polar solvents, while in non-polar solvents, it is prone to swelling and other aging-resistant phenomena, so it is not resistant to oil and non-polar solvents.
The disadvantages of natural rubber stoppers are summarized as follows: (1) poor air tightness (2) poor chemical resistance (3) poor aging resistance (4) poor high temperature resistance and radiation resistance (5) poor weather resistance (6) difficult to separate due to the high content It contains more protein and other substances, and its purity is low.
2. The main component of butyl rubber is polyisobutylene. However, the methyl group in polyisobutylene has a large steric barrier, so the thermal motion of the molecule is not active, so its gas permeability is the smallest in synthetic rubber, and the molecular The number of double bonds in the main chain is very small, so the UV resistance and ozone resistance are very good, and the heat resistance is also very high. And butyl rubber is non-polar, so it has good resistance to polar solvents, so it can give drugs good chemical stability. The advantages of butyl rubber stoppers are summarized as follows: (1) It has good air tightness and minimal air permeability. (2) Good high temperature resistance. (3) Good ozone resistance and weather resistance. (4) Alkali and acid medium solvent. (5) Poor water absorption and good radiation resistance