Chemical Properties of Plastics | The Ultimate Guide

Hello people; I’m sharing a salient guide on plastic chemical properties today. Keep reading to get some exciting information about plastics.

Chemical Properties of Plastics 

The chemical properties of plastics are mainly influenced by the type of monomer used in their production and their chemical structure. Typically, plastics are produced from petroleum-based chemicals such as styrene, vinyl chloride, ethylene, propylene, and others.

These monomers are subjected to polymerization under specific conditions such as high temperature, pressure, and catalysts, resulting in long chains of repeating units referred to as polymers. Various additives like plasticizers, stabilizers, pigments, and flame retardants can be introduced to the resulting plastic to improve its performance and properties.

One of plastics’ most essential chemical properties is their resistance to degradation. Most plastics are resistant to chemical and biological degradation, so they are durable. However, this feature is also accountable for their prolonged existence in the environment since they can take hundreds of years to break down naturally.

The functional groups in their polymer chains determine the plastic chemical properties. For example, polyethylene and polypropylene have only carbon and hydrogen atoms in their chains, which makes them inert and resistant to chemical reactions. On the other hand, polystyrene and polyvinyl chloride contain functional groups such as aromatic rings and chlorine atoms that make them more reactive and potentially toxic.

How Chemical Properties of Plastics Affect Its Processing

The chemical properties of plastic material are crucial in the manufacturing process, as they dictate the techniques used to produce the final product. Knowledge of these properties is vital for improving manufacturing, guaranteeing high-quality and uniform products, and reducing environmental impact.

Melting Point

The melting point of polymer is a significant chemical property that impacts plastic processing. Plastics with lower melting points, like polyethylene, are amenable to processing techniques like extrusion or injection molding. In contrast, plastics with higher melting points, like polypropylene or polyamide, require extra processing measures like annealing or stretching to achieve the desired properties.

Molecular Weight 

Polymer molecular weight is a vital chemical property that impacts the processing of plastics. High molecular weight polymers, such as HDPE, pose more challenges in processing than low molecular weight polymers like LDPE. This is because high molecular weight polymers require higher processing temperatures and pressures to achieve the desired properties, which can increase energy usage and processing costs.

Rheological Properties

During processing, the rheological properties of a plastic, including viscosity, elasticity, and shear modulus, influence its behavior under flow and deformation. These properties can impact the plastic’s ability to flow through processing equipment, such as extruders or injection molding machines, and ultimately impact the final product’s properties, such as strength, flexibility, and surface finish.

Therefore, a thorough understanding of the rheological properties of plastics is critical for optimizing processing conditions and ensuring that the final product has consistent quality.

Chemical Resistance of Polymers 

Here is a table showing the chemical resistance of different plastic materials:

Plastic Material
Chemical Resistance
Polyethylene (PE)
Resistant to acids, alkalis, and most solvents; not resistant to strong oxidizing agents
Polypropylene (PP)
Resistant to most acids and alkalis; not resistant to strong oxidizing agents
Polyvinyl Chloride (PVC)
Resistant to acids, alkalis, and some organic solvents; not resistant to polar solvents or strong oxidizing agents
Polycarbonate (PC)
Resistant to acids, alkalis, and most organic solvents; not resistant to strong oxidizing agents
Acrylonitrile Butadiene Styrene (ABS)
Resistant to acids, alkalis, and most organic solvents; not resistant to strong oxidizing agents
Polyethylene Terephthalate (PET)
Resistant to weak acids and alkalis; not resistant to strong acids or polar solvents
Polyurethane (PU)
Resistant to oils, greases, and some solvents; not resistant to strong acids or alkalis
Polystyrene (PS)
Resistant to non-polar solvents; not resistant to polar solvents, acids, or alkalis
Polyamide (PA)
Resistant to most organic solvents and some acids; not resistant to strong alkalis or oxidizing agents


To conclude, the chemical properties of plastics play a crucial role in determining their viability for different applications. Variables such as monomer selection, molecular weight, functional groups, and additives affect the mechanical, thermal, and plastic chemical properties, influencing their durability, performance, and processing.

It is vital to comprehend these properties when selecting the appropriate plastic for a particular application and to develop new plastic products. Moving forward, plastics technology must balance cost, performance, and sustainability while considering the diverse needs of industries and consumers.

Thanks for reading. Have a wonderful day.

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