The main methods for modifying the heat resistance of plastics include additive modification, blending modification, crosslinking, morphology control, and lamination treatment. Additive modification is one of the most important and effective methods for changing the heat resistance of plastics. Additive modification can be divided into two parts according to cost: filling and reinforcement. Some halogen-free flame retardants, such as aluminum hypophosphite, cannot be used in high-temperature PAs, while some fillers also have adverse effects on ADP flame retardants. Heat stabilizers can also be added to modify the heat resistance of plastics; different types of heat stabilizers are used for different plastics.

Blending to modify the heat resistance of plastics involves mixing high-heat-resistant resins into low-heat-resistant resins, thereby improving their heat resistance. Although this method does not improve heat resistance as much as additive modification, it can modify the heat resistance while largely preserving the original plastic properties. Crosslinking modifies the heat resistance by forming fixed chemical bonds between macromolecular chains, thus increasing the difficulty of macromolecular movement. As temperature increases, macromolecular chains can only move at high temperatures, and do not deform at the original non-crosslinked heat distortion temperature, thus increasing the heat distortion temperature.

Morphological control mainly refers to controlling the crystallization, orientation, and post-processing of plastics during molding. Orientation is an effective method for heat resistance modification. Plastic lamination alters the heat resistance of plastics by attaching a heat-resistant material to the surface of the plastic product, thereby improving its heat resistance. Depending on the lamination material, it can be divided into two main categories: heat-resistant coatings and heat-resistant platings.