Brief History of Plastics

In 1893, a man named Charles Goodyear found natural rubber. Polystyrene then appeared and become recognized by the year 1938. Polyamide came out in 1939, PP in 1941, and LCP in 1985. In 1978, PEEK came into the market and 5 years later PEI (also called Ultem) was first made by GE.

In these years, thousands of types of resins were developed for sale. Among these types, thermoplastics, thermo-settings, and elastomers are only a drop in the ocean.

How to choose the proper plastic in your products? Your knowledge in the school and your experience from plain work may still be helpless for many designers and engineers.

 

Part 1: PE, PP & PA

Foreword

More and more materials we can see today contain plastics. Our daily supplies, such as wood, metal, and leathers are also replaced by plastic products gradually. It’s obvious that plastics are changing our life, including our work and recreation. Sometimes plastics may cause pollution, however, they are undoubtedly indispensable to modern society.

We suggest you think about the following aspects first:

In what conditions should my product run?

Does it have to work in extreme temperature?

Does it contact with the human body or other living creatures?

Is it self-lubricating or water-absorbing?

Then you can choose the best solution according to the following introduction.

PE-1

PE (Polyethylene)

With 80-million-tons annual consumption, PE is the most popular plastic. The commonest application is packaging, especially in plastic bags.
Early appeared in 1898, PE had not been mass-produced until a standard technology was developed by a British scientist in the 1930s. LDPE was developed in 1939 and then HDPE in 1953 by a researcher in Phillips Petroleum.
HDPE and LDPE are widely used in packages and containers. LDPE film is a material of plastic bags, and the cover of paper boxes (e.g. milk box). Through blow-molding, they may become containers and storage fitments. Through injection molding, they may become household appliances like mops and buckets.

PP (Polypropylene)

Paul Hogan and Robert L. Banks, scientists in Phillips Petroleum, developed PP in 1955.

PP is durable and economic. The relatively high tensile strength allows PP a larger compressive deformation. It is resistant to many acids, solvent, and chemicals. PP is widely used in many industries, especially pharmaceutical fields for its chemical resistance and non-toxic features.

PP is both tenacious and flexible. It is an ideal alternative to ABS.

PP-1
PA-1

PA (Polyamide, Nylon)

Nylon is an engineering thermoplastic composite of quadrol. It was first used in Dupont as a fiber in 1938. Injection-molded PA was developed in 1941.
There are 3 common types of Nylon: PA6, PA66, and PA12. The main advantages are wearability and weatherability. Therefore PA is often used in gears, bearings, and soleplates. PA is also combined with additives, for example, glass fiber as reinforcement. However, it is water absorbable, which may cause trouble in some cases.

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