Adding impact modifiers to plastic compounded materials can help enhance the impact strength and durability of various plastic resins. Weak impact resistance is generally a performance defect observed in certain plastics, such as PVC, PP, and PS, mostly at low temperatures, which limits their application due to low impact resistance. Thus, adding impact modifiers is the best way to achieve high impact resistance.
Types of Impact Modifiers
A wide variety of impact modifiers can be used to improve impact resistance and material resistance. The most commonly used are core-shell impact modifiers, methyl methacrylate-butadiene-styrene copolymer (MBS), ternary Ethylene propylene rubber (EPT), acrylonitrile butadiene styrene (ABS), acrylate resin (ACR), chlorinated polyethylene (CPE), and ethylene vinyl acetate (EVA). These modifiers give plastics excellent toughness, improve processing performance, and enhance the low-temperature embrittlement of plastic products.
Low-Temperature Impact Modification
Most plastic products at room temperatures demonstrate their typical properties of flexibility and tough resistance to cracking. However, these properties can change dramatically when the temperature reduces, causing plastics to become brittle.
Low temperatures are especially more damaging than high temperatures. Meaning low-temperature impact toughness is required for applications that need some degree of low-temperature flexibility.
Various impact modifiers can be applied to ABS, engineering plastic, PVC, and general plastic to improve both chemical and physical impact properties like impact resistance, improved durability, weather resistance, and study elongation strength of low temperature and excellent modification.
General Purpose Impact Modification
This provides a low-level impact modification usually applied to prevent the conditioning of molded plastic products. General-purpose impact modification translates to average room temperature impact performance but does not consider any need for low-temperature impact strength.
For most general-purpose modifications, only low-level impact modifiers are needed. In addition, these impact modifiers do not have to carry reactive compounds to fit in the application.
This type of impact strength is essential for plastic applications that should not break even when exposed to low temperatures at high speed. Only high levels of reactive impact modifiers are suitable for plastic materials that require super toughness.
Impact modifiers can help enhance material features, such as processability, heat distortion, flammability, weatherability, and tensile properties.
How Impact Modifiers Work
The impact modification process entails introducing an element that’s elastomeric (rubbery) in nature to help dissipate the energy of impact. You can incorporate impact modifiers through polymerization in the reactor or as an additive during the compounding process. Essentially, the impact modifiers work via two mechanisms.
The first mechanism is craze propagation which involves dispersing the modifiers into a brittle matrix, where they absorb energy. The shear cavitation mechanism works by forming shear bands within the rubbery particle, sucking up deformation energy.
Buy Impact Modifiers at Bisley International
Bisley International offers a wide variety of acrylic impact modifiers, including AIM-659, AIM-AM81, AIM-LS61, and more, that ensure PVC production with faster extrusion and a greater processing window, and higher output. For further details, please visit the Bisley website or contact us for inquiries.
Check out our raw materials guide for PVC Plastics, Rubbers & Foam