Chapter Guide
Common Chain-Growth Polymers
Chain-growth polymer families cover many familiar plastics, elastomers, coatings, standards, and specialty materials. The monomer side group, polymerization route, and copolymer composition explain most of their property differences.
Family Map
| Family | Representative Polymers | Property Signal |
|---|---|---|
| Polyolefins | Polyethylene, polypropylene, polyisobutylene, poly(4-methyl-1-pentene). | Low polarity, crystallinity and branching dominate density, melt flow, and stiffness. |
| Diene polymers | Polybutadiene, polyisoprene, chloroprene rubber, styrene-butadiene rubber. | Microstructure, unsaturation, vulcanization, and oxidation resistance matter. |
| Styrenics | Polystyrene, SAN, ABS, SMA, styrene-isoprene-styrene block copolymers. | Aromaticity raises RI and stiffness; copolymers tune toughness and polarity. |
| Acrylics and methacrylics | PMMA, polyacrylic acid, poly(n-butyl acrylate), poly(ethyl methacrylate). | Side groups tune Tg, polarity, solubility, adhesion, and optical clarity. |
| Acrylonitrile polymers | Polyacrylonitrile and acrylonitrile copolymers. | Polar nitrile groups affect Tg, solvent resistance, fibers, and carbon-fiber precursor behavior. |
| Vinyl polymers | PVC, PVAc, PVA, PVF, PVP, poly(vinylbenzyl chloride). | Side-group chemistry controls solubility, Tg, reactivity, and safety context. |
| Fluorinated polymers | PTFE, PVF, fluorinated specialty polymers. | Low surface energy, chemical resistance, density, and optical behavior vary by fluorination. |
Polyolefins
Polyolefins are hydrocarbon polymers with low polarity and strong structure-processing relationships. Branching, tacticity, comonomer content, and catalyst system shape crystallinity, density, melt flow, and mechanical behavior.
Polypropylene
Tacticity, crystallinity, density, solubility, and commodity-plastic context.
Polyisobutylene
Cationic polymerization, tack, oil solubility, and elastomeric behavior.
Olefins Hub
Family-level navigation for hydrocarbon polymers and related property pages.
Styrenics, Dienes, and Rubbers
Styrene adds an aromatic side group that raises stiffness and refractive index. Diene monomers create unsaturated backbones where microstructure and crosslinking dominate elastomer properties. Copolymers such as SAN, ABS, SBR, and SIS combine these behaviors in useful ways.
- Polystyrene is useful for standards because narrow-distribution grades can be prepared and characterized.
- High-impact polystyrene and ABS use rubber phases to improve toughness.
- SAN increases polarity and heat resistance compared with polystyrene but changes processing and solvent response.
- Polybutadiene and polyisoprene properties depend strongly on cis, trans, and vinyl microstructure.
Acrylic, Methacrylic, and Vinyl Polymers
Acrylic and vinyl families are chemically broad. PMMA is rigid and transparent, poly(n-butyl acrylate) is soft, polyacrylic acid is water-responsive, PVC is halogenated and formulation-sensitive, and poly(vinyl alcohol) is usually made by hydrolysis of poly(vinyl acetate).
| Polymer | Key Chemistry | Site Use |
|---|---|---|
| PMMA | Methacrylate ester with high optical clarity. | RI, density, solubility, and acrylic reference pages. |
| Polyacrylic acid | Carboxylic acid side groups, pH response, hydration. | Solubility, SDS, density, molecular weight, and buying notes. |
| PVC | Chlorinated vinyl polymer, often heavily formulated. | Density, RI, SDS, molecular weight, and plasticizer context. |
| Poly(vinyl alcohol) | Hydroxyl-rich polymer from hydrolyzed PVAc. | Solubility, structure, and hydrogen-bonding context. |
How to Compare Chain-Growth Materials
- Identify monomer structure and side-group chemistry.
- Record polymerization route, catalyst or initiator family, and residuals when available.
- Record molecular weight, dispersity, and calibration method.
- Check tacticity, branching, microstructure, and copolymer sequence.
- Compare density, RI, Tg, crystallinity, and solubility only under compatible grade conditions.