One application is truck liners. For years, truck liners were made with glass reinforced polyester thermosets, which were easily damaged. “The thermoplastics [liners] ended up being much more puncture proof. They would take the abuse more than the polyester thermal liners,” says Pilpel. “Most companies have switched over completely to thermoplastic [composites] now.”
3. Engineering Polymers
Morgan says the expansion of engineering resins – with long and short carbon fiber reinforced polyamides and high-performance polyphthalamides – are key drivers to the spread of thermoplastic composites. Unlike less expensive commodity resins, engineering polymers offer exceptional mechanical properties at elevated temperatures, increased stiffness and toughness, and low creep. This makes them ideal for more metal-to-plastic structural components opportunities.
For decades, Morgan says the automotive sector used “the pretty polymers” – acrylonitrile butadiene styrene and polycarbonate – to make aesthetic, interior composite parts, such as interior trim. Now, automakers are turning to polyphthalamide (PPA) thermoplastic and carbon fiber reinforced polyamide composites for more structural parts. For example, Ford uses Ultramid® short carbon fiber polyamide to manufacture a chassis part for the Shelby GT350 Mustang and has demonstrated advanced powertrain parts in long carbon fiber polyamide.
Morgan says PPAs are important because they enable the conversion from heavier steel parts to lighter composite parts that wasn’t previously possible. “Engineering plastics will play a big role in helping OEMs cost effectively meet emission and fuel efficiency standards,” she says.
Morgan adds that advanced thermoplastic polymer composites also enable many digital technologies, including advanced driver-assistance systems designed to automate and enhance vehicle systems for safer driving. PPAs are used to fabricate the many censors and electrical connections these systems require because they are small, thin and light and have high temperature tolerances that allow them to be safely packed together in small spaces.
4. Compression Molding
While not as widely used as injection molding – especially in the United States – compression molding can be a lower cost alternative. “It won’t be as fast as injection molding, but if you are making fewer parts, it’s a lot less costly to build the mold,” says Pilpel.
Compression molding can also produce higher fiber parts. Pilpel says the University of Alabama at Birmingham’s Materials Processing & Applications Development Center has used selective reinforced compression molding to achieve 65 to 70 percent fiber content – a marked contrast to injection-molded parts that typically yield 30 to 40 percent. Higher fiber content can help maximize properties, especially stiffness, for applications where that is important.