Senior Scientist Richard Bopp received welcome news from his company’s production facility in Blair, NE. Making a call before his 9:00 am presentation, Bopp verified that the plant had successfully doubled its production capacity for corn-derived polylactic acid (PLA) resin from 150-million lb/yr, to 300-million lb/yr, with the site producing prime product.
In addition to feeding the broadening segment within single-serve and packaging markets that PLA has staked out, Bopp told attendees the new output would also aid the company’s push into durable applications, saying current research should allow the company to release a high-heat injection moldable grade later this year. “The work we’re doing is on durable applications,” Bopp said. “PLA has formed a niche in packaging, but because of the some of the developments made while working on packaging, we feel like we can move into more durable applications.”
Among those developments, was the creation of a single-stage CPLA (crystallized PLA) for the thermoforming market, which utilizes EBS (ethylene bis stearamide) as a nucleating agent. The company is experimenting with different nucleating agents for an injection moldable PLA, as well as shooting the resin into a hot tool, to overcome some of the material’s current deficiencies.
Bopp stressed that those shortcomings, contrary to popular opinion, are more related to the time needed for PLA to crystallize vs. its heat deflection, saying the resin has a “process-time issue” instead of a “heat issue.” To enter into durable injection-molded products, the company is also weighing impact toughening through rubber modification, specialty minerals, and biaxial orientation, as well as working to address concerns regarding hydrolytic stability and ignition resistance.
Bopp believes the key to overcoming some of the issues revolves around advances in stereochemistry. The left-hand/right-hand symmetry of the PLA molecule is important to crystallization, with stereocomplex constructs pushing the biomaterial’s heat performance to 220°C, according to Bopp. The research has already driven PLA into new applications, including the replacement of high-impact polystyrene in hot coffee lids, but the goal is to enter new markets. Bopp pointed out that crystallization also boosts mechanical properties, pushing the melt impact into the 160°C region, compared to a glass-transition of 60°C for non-crystallized PLA, further increasing the material’s potential appeal. —[email protected]