Application of Nanotechnology in Pharmaceutical Packaging Materials

In pharmaceutical packaging, in order to have high impact strength, softness, transparency, etc., it is necessary to choose plastic materials, to make an introduction to plastic materials.
â–¼ The properties of plastics to be printed are mainly determined by the size and shape of their constituent molecules. Most of the plastics are monomeric at the first few stages of manufacture, that is, they are composed of small-sized molecules, but the heat and pressure Under the action of chemical catalysts, these small molecules combine into complex molecules and become solid or semi-solid structures. The properties of plastic can be listed as follows:
1. Resistant to chemical attack.
2. Glossy, partially transparent or translucent.
3. Most plastics are good insulators.
4. Lightweight, but strong, can even replace metal.
5. It can be mass-produced, easy to process, and inexpensive.
6. Wide range of uses, effectiveness and color.
7. Physical stability, good electrical properties.
8. With flexibility, easy to color, some high temperature.

Plastics have many advantages as mentioned above, and new plastics have also been continuously researched and developed, and its various properties are more excellent, such as engineering plastics or polymer plastics.

High-molecular polymers are high-molecular-weight compounds that contain a covalent bond as a binding atom or a binding force between molecules. In general, a molecular weight of 1,000 or more can be referred to as a polymer. In nature, natural rubber, protein, cellulose, starch, and asbestos are all high molecular substances.
Polymer is composed of monomers, that is to say, polymers are bound by monomers. Structural units are usually used to describe the structure of polymers. Structural units have different arrangements and links. The method, for example a linear polymer, has the structure unit arranged in the chain as X-(M)nY, where M is a structural unit, ie, a monomer, and n is the degree of polymerization (degree of Polymerization), abbreviated dp. When n is 2, they are called dimers. When n is 3, they are called trimers. When n is 4, they are called tetramers. The number of n can be up to 10 million. About two ends of the structural unit M are bonded by X and Y, and X and Y may be the same or different. Polymers that contain the same repeating units are called homopolymers, such as polyethylene. Polymers containing two or more structural units, called copolymers. The polymerization forms include addition polymerization, condensation polymerization and combination polymerization.

â–¼ Commonly used plastic printed materials can include the following:

1. Polyethlene
The abbreviation PE is the most widely used plastic. The main raw material of polyethylene is ethylene. Can make use of the thermal cracking of pentane to produce ethylene: Pentane pressure cracking, available ethane and propylene, ethane and then dehydrogenation reaction can be ethylene. Its main products are polyethylene lids, cutlery, kitchen supplies, toys and lighting parts.
Polyethylene can be divided into two types, low density polyethylene and high density polyethylene. Low-density polyethylene, with a molecular weight of 50,000 to 300,000, a density of about 0.92 g/cm3 high-density ethylene, a molecular weight of up to 3 million, and a density of about 0.96 g/cm3.

2. Polypropylene
Polypropylene is produced in the same way as polyethylene, with titanium trichloride and triethylaluminum, tributylaluminum or diethylaluminum chloride as activators. It is dispersed in a solvent and reacts at 10 atmospheres. The reaction produces Polypropylene is slurried, soluble in ethanol, dried after processing.
Polypropylene is harder than polyethylene, has a high softening point and is brittle at low temperatures. The molecular weight is between 80,000 and 150,000, with a specific gravity of 0.90 to 0.91. Related products include the manufacture of silk fibers, transportation equipment, laboratory glass, dropper and injection molding products.

3. PVC (pvc)
The Chinese name is polyvinyl chloride, and its material properties are high in specific gravity and flame resistance. With high transparency, good insulation and good printability. Different formulations have different characteristics, wide application and low cost. When the processing temperature exceeds 190°C, cracking occurs easily, and HCL gas is released. Great environmental impact. Molecular weight between 60,000 and 150,000, with good electrical resistance, fire resistance and so on. The related products are wire and cable jackets, raincoats, and curtains. Addition of additives can make the record.

4.Pet polyethylene terephthalate (polyester)
The Chinese name is polyethylene terephthalate (polyester). Its material properties are low specific gravity, no moisture absorption, good insulation, transparency, low cost, and low rigidity.

5.ABS (acrylonitrile-butadiene-styrene tri-copolymer)
The Chinese name is acrylonitrile-butadiene-styrene tri-copolymer. The material properties are the proportion of each polymer, ABS with different characteristics, surface strength and heat resistance are all very good, the surface gloss is good, the surface is sprayed and galvanized, hygroscopic, and the general finished product can be dyed Need color. Its related printing products are suitcase surface plates, ABS tubes, and home appliance shells.

6.PC (polycarbonate)
The Chinese name is polycarbonate. Its material properties are good transparency, high impact resistance at room temperature, high temperature resistance, high rigidity, FDA grade, poor abrasion resistance, and poor chemical resistance. Its related printing products include safety glass and transparent containers for medical equipment.
Table 1 Physical Properties of Polyethylene Low Density Polyethylene High Density Polyethylene Molecular Weight 50000~300000 300000~3000000
Tensile strength (lb/in2) 1800~2000 3500~4500
Melting point 110 124~135
Elongation % 600 100
Methyl group 21.5 1.5~3
Crystallinity 60% 90~95%
Dielectric constant 2.3 2.3