plastics

Plastics are a broad category of materials composed mainly of synthetic or semi-synthetic organic polymers. They are typically derived from petrochemicals and can be molded into complex shapes. Plastics are commonly classified into thermoplastics, which soften when heated, and thermosetting polymers, which cure into a rigid network.

The modern plastics industry emerged in the late 19th and early 20th centuries, with Bakelite and later polyethylene transforming manufacturing. After World War II, advances in polymer chemistry and mass production led to rapid adoption in packaging, construction, electronics, and automotive sectors.

Widely used plastics include polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polystyrene (PS), and polyethylene terephthalate (PET). Different polymers have varying properties—stiffness, clarity, chemical resistance, and heat tolerance—often enhanced with additives such as plasticizers, stabilizers, or colorants.

Plastics offer advantages such as light weight, durability, corrosion resistance, and design flexibility. They may degrade under heat or UV light, release additives, and pose health concerns in some applications. They can persist in the environment long after disposal.

Environmental challenges include accumulation in landfills and ecosystems, fragmentation into microplastics, and emissions from waste processing. Global production affects energy use and greenhouse gas emissions, prompting interest in recycling and alternatives.

Recycling methods include mechanical recycling, which reprocesses plastics into pellets, and chemical or feedstock recycling, which breaks polymers down to monomers. Rates vary by polymer and region and are affected by contamination and packaging design. Policies promote producer responsibility, bans on some single-use plastics, and better waste management.

Research focuses on improving recyclability, bio-based or biodegradable plastics, and chemical recycling technologies to close material loops and reduce environmental impact.