Why are whiskers added to plastics?

The addition of whiskers to plastics is mainly to improve the properties of plastics, including enhancing their mechanical properties, heat resistance, wear resistance, flame retardancy, etc.

Enhance mechanical properties

Whiskers possess high strength and modulus. For instance, the strength of silicon carbide whiskers can approach their theoretical strength. When added to plastics, they can act like a framework to withstand external forces, effectively enhancing the tensile strength, bending strength, and impact strength of plastics. This makes the originally relatively soft and easily deformable plastics more robust and durable, and they can be used in structural components and other application scenarios that are subjected to significant external forces.

Improve thermal stability

Some whiskers themselves have good high-temperature resistance. When they are uniformly dispersed in the plastic matrix, they can to a certain extent hinder the vigorous movement of plastic molecular chains at high temperatures, delay the thermal deformation of plastics, increase the thermal deformation temperature of plastics, and thereby expand the operating temperature range of plastics. For example, the casings of some electronic and electrical components that work in high-temperature environments can benefit from this.

Improve dimensional stability

Whiskers in plastics can play a role in restricting the shrinkage of the base material, reducing the dimensional changes caused by factors such as temperature and humidity during the molding cooling process and subsequent use of plastics. For some plastic products with high requirements for dimensional accuracy, such as plastic parts of precision instruments, adding whiskers can better ensure their dimensional stability.

What types of whiskers are there?

Silicon carbide whiskers

It has the advantages of high strength, high modulus, high temperature resistance and good chemical stability, which can significantly improve the comprehensive performance of plastics. It is often used to prepare high-performance plastic parts in fields such as aerospace and automotive industries, such as some plastic structural parts around aero engines that are subject to high temperatures and mechanical loads.

Potassium titanate whiskers

It has excellent thermal insulation, chemical corrosion resistance and good mechanical properties. While reinforcing plastics, it can also endow plastics with certain wear resistance, heat insulation and other characteristics. It is often used in the field of friction materials, such as plastic matrix composites for brake pads, as well as some plastic pipes and other products that require good chemical protection performance.

Calcium carbonate whiskers

It has a relatively wide range of sources and low cost, and can achieve certain reinforcing and toughening effects. It can also improve the processing fluidity of plastics. It is widely used in the modification of general plastics, such as some ordinary plastic building materials and daily plastic products, to enhance performance and control costs by adding calcium carbonate whiskers.

Calcium sulfate whiskers

It features non-toxicity, odorlessness, high whiteness and good stability. Besides enhancing mechanical properties, it can also endow plastics with better appearance characteristics. It is often used in plastic products with high requirements for hygiene and appearance, such as food packaging and medical equipment, to increase the strength of the products while ensuring safety and aesthetics.

Zinc oxide whiskers (ZnOw)

Performance features: Zinc oxide whiskers possess high-temperature resistance, thermal conductivity and a low coefficient of expansion, which can enhance the chemical and dimensional stability of materials at high temperatures. It can also improve the mechanical properties of materials, such as tensile strength, bending resistance and wear resistance, and has the functions of antibacterial, ultraviolet and infrared absorption. It can be used to prepare functional composite materials, such as antibacterial refrigerators, telephones, food bags and floors, etc.

Magnesium borate whiskers

Performance characteristics: Magnesium borate whiskers exhibit excellent reinforcing properties and feature light weight, high toughness, wear resistance, and corrosion resistance. It can be used for heat-resistant and wear-resistant components such as engine pistons, connecting rods, compressor cylinders, automotive brake pads and clutch linings.

Aluminum borate whiskers

Performance characteristics: Aluminum borate whiskers have a high elastic modulus and good mechanical strength. It features heat resistance, chemical resistance, acid resistance, electrical insulation, etc. It can be used in insulating, heat-resistant and corrosion-resistant materials, and also as a reinforcing agent for thermoplastic resins, thermosetting resins, cement, ceramics and metals.

Magnesium sulfate whiskers

Performance features: Magnesium sulfate whiskers have high strength, high modulus, good electrical properties, good compatibility with plastics, and the composite material exhibits excellent physical and mechanical properties. They also have the characteristics of being non-toxic, having low smoke emission, and being flame retardant. It can be used to prepare composite materials in matrices such as plastics and rubbers, endowing the composite materials with flame retardant properties and achieving dual effects of reinforcement and flame retardancy.

What are the performance characteristics of whiskers?

Height-to-diameter ratio

Whiskers generally present a slender fibrous morphology with a relatively large length-to-diameter ratio. This enables them to form an effective stress transmission network in the plastic matrix. When the plastic is subjected to external forces, whiskers can better disperse the stress and prevent stress concentration from causing premature material failure.

High strength and high modulus

Its own crystal structure is relatively complete with few internal defects, so it has a very high strength and elastic modulus. This is an important basis for them to enhance the mechanical properties of plastics, making plastics less likely to deform and break during load-bearing.

It has good chemical stability

Most whisker materials are not prone to chemical reactions under normal chemical conditions and can stably exist in the plastic matrix, ensuring that they continuously play reinforcing and other roles throughout the service life of plastic products and will not fail due to chemical corrosion or other reasons.

The application of whiskers in plastics

The field of electronics and electrical appliances

It is used to manufacture the casings of electronic devices, circuit board support parts, etc. By adding whiskers to enhance the performance of plastics, these components can better withstand mechanical shock, thermal stress, etc. during use, while ensuring good dimensional stability to guarantee the normal operation and reliability of electronic and electrical equipment, such as the casings of computer hosts and some plastic brackets inside mobile phones.

The field of the automotive industry

It is applied in interior parts of automobiles, plastic components around engines, etc. For instance, in automotive instrument panels, some pipelines in the engine compartment, etc., plastics reinforced with whiskers can meet the requirements of various aspects such as material strength, heat resistance and chemical resistance in the automotive usage environment.

Aerospace field

Given the strict requirements for high performance of materials in the aerospace industry, plastics with added whiskers can be used to manufacture some structural components inside aircraft and parts of satellites, reducing weight while being able to withstand complex stresses and temperature changes in the space environment, ensuring the smooth progress of aerospace missions.

Construction industry

For building plastic products such as plastic doors and Windows and plastic pipes, adding whiskers can enhance their strength, rigidity and weather resistance, extend their service life, and better meet the requirements of building structure and usage function.

What are the characteristics of POM whiskers? Specific application fields? Currently, it is added to the market

POM whiskers have the following characteristics:

High strength and high modulus: POM whiskers have a strength close to the theoretical value of a complete crystal. Their atomic arrangement is highly orderly, with few internal defects and high mechanical strength, which can effectively enhance the mechanical properties of POM plastics, making them more robust and durable.

Good dimensional stability: After being added to POM, it can microscopically change the structure of the product, making the longitudinal and transverse shrinkage rate differences of the product small in various environments, thereby ensuring the precision of the product's size and shape, reducing warping and deformation, and is very beneficial for manufacturing precision components.

Enhance wear resistance and sliding performance: It helps to improve the wear resistance of POM, reduce the coefficient of friction, and enable POM products to perform better in applications with frequent sliding or friction. For instance, when manufacturing various mechanical parts such as gears, bearings, and pulleys, it can effectively reduce wear and extend service life.

Improving thermal stability: It has certain high-temperature resistance, which can increase the heat distortion temperature of POM, expand its operating temperature range, and enable POM products to maintain good mechanical properties and dimensional stability even in high-temperature environments.

Good dispersibility: It can achieve good dispersion in the POM matrix, has good compatibility with POM materials, forms uniform composite materials, fully exerts its reinforcing and toughening effects, and at the same time will not have a significant negative impact on the processing performance of POM.

Good surface finish: Although the length-to-diameter ratio is large, the size is very small. When used to reinforce POM products, it is more lustrous and flat than long fiber reinforced products, which can improve the appearance quality of the products and make them more suitable for occasions with high requirements for surface finish.

The specific application fields of POM for adding whiskers are as follows:

The automotive industry: It is used to manufacture components such as car bumper brackets, window control systems, inner door handles of cars, oil pump bearing seats and impellers, and gas switch valves. By taking advantage of its high rigidity, dimensional stability, wear resistance and chemical resistance, it can ensure the stable and reliable operation of automotive parts in complex usage environments.

In the field of electronics and electrical appliances: It is suitable for manufacturing the shells of equipment such as copiers, refrigerators, electric fans, televisions, washing machines, tape recorders, computers, printers, etc., as well as electronic switch parts, terminal post mirror masks and other components. With its excellent dimensional stability, electrical insulation and mechanical properties, it ensures the normal operation and service life of electronic and electrical equipment.

Mechanical manufacturing: It is an ideal material for manufacturing various mechanical parts, such as gears, bearings, levers, pulleys, sprockets, etc., which can meet the requirements of these components to withstand greater stress in mechanical equipment, improving the reliability and stability of the equipment.

In the field of medical devices: It can be used to manufacture drug inhalers, insulin pens and other injection devices for chronic obstructive pulmonary disease (COPD) and asthma, as well as other medical device components. Medical device parts made of POM whisker-reinforced materials have the advantages of low noise, high rigidity and dimensional stability, which can improve the comfort and safety of use.

In the field of daily necessities, it is also applied in the manufacturing of some daily necessities, such as zippers and other products. By taking advantage of its wear resistance, dimensional stability and other properties, the quality and service life of the products are improved.

Which manufacturers add whiskers to POM and other materials for adding whiskers?