What are the differences in thermal expansion coefficients between these plastics?

Thermal expansion coefficients vary significantly among different types of plastics, influencing their suitability for specific applications. Generally, thermoplastics like polyethylene (PE) and polypropylene (PP) exhibit higher coefficients, expanding more under heat, while engineering plastics such as polycarbonate (PC) and acrylonitrile butadiene styrene (ABS) have lower values. For instance, PE's coefficient ranges around 200 x 10^-6/°C, whereas PC's is closer to 70 x 10^-6/°C. These differences arise from molecular structure—amorphous plastics (e.g., polystyrene) expand more than semi-crystalline ones (e.g., nylon). Understanding these variations helps in selecting materials for environments with temperature fluctuations, ensuring dimensional stability and performance. Always consult technical datasheets for precise values tailored to your project needs.