Tread Bar

Plastics are macromolecular compounds (macromolecules), commonly known as plastics or resins, made by polymerizing monomers as raw materials through polymerization or condensation. The composition and shape can be freely changed. It consists of synthetic resins, fillers, plasticizers, stabilizers, lubricants, colors, and other additives.

The main component of plastic is resin. Resin is a term originally given to lipids secreted by plants and animals, such as rosin and shellac, etc. Resin is a polymer that has not yet been mixed with various additives. Resin accounts for about 40% to 99% of the total weight of plastic. The basic properties of plastics are mainly determined by the nature of the resin, but additives also play an important role. Some plastics are basically composed of synthetic resins and contain no or few additives, such as plexiglass and polystyrene. The so-called plastic is in fact one of the synthetic resins, similar in shape to the pine resin in natural resins, but is called plastic because it has been synthesized by chemical means.

Definition

According to the definition of the American Society for Testing and Materials (ASTM), plastic is a material with high molecular weight organic substances as its main component, which is solid when it is processed, and can be shaped by flow during manufacturing and processing.

Therefore, we can understand the following from this explanation:

It is a polymer organic compound.

It can exist in various forms, such as liquid, solid, and colloidal solutions.

It is moldable.

There are many kinds of plastics because different monomers and their compositions can be synthesized.

There is a wide variety of uses and products.

It has different properties.

Can be processed by different processing methods.

The terms plastic and resin are often used interchangeably.

Classification

Plastics can be categorized into thermosetting, which cannot be reshaped, and thermoplastic, which can be produced over and over again. There are basically two types of plastic polymer structures: one is the linear structure; the second is the bulk structure.

Classification of the molecular structure of polymers:

(a) Linear structure

(b) Linear structure (with branched chains)

(c) reticular structure (a small amount of cross-linking between molecular chains)

(d) Bulk structure (large number of cross-links between molecular chains)

Two different structures, dissolution; body structure polymers have no elasticity and plasticity due to the absence of independent macromolecules, so they cannot be dissolved and melted, only dissolved.

Table 1.1 for the plastic raw materials cross-reference table, 1 to 8 items for generalized plastics, the 9th. 10th between the two. Generally known as PP, HDPE, LDPE, PVC and PS for the five major general-purpose plastics.