Three previously announced families of renewably sourced polymers for packaging and engineered products are now commercially available from DuPont Co., Wilmington, Del. As we reported last November, Biomax TPS resin and sheet (see p. 27) are cornstarch-based materials from Australia's Plantic Technologies. They are available here from DuPont Packaging & Industrial Polymers. Biomax TPS (thermoplastic starch) resin pellets with 85% to 90% renewable content come in a g-p injection grade and a high-flow grade for thin- wall parts. A stiffer engineering grade and two water-resistant materials will be launched soon. Injection grades are certified to meet EN 13432 and BPI standards for industrial composting and are for short-life, single-use outdoor applications such as lawn and garden products. DUPONT SORONA EP BIO-BASED PTT RESIN

DuPont is also commercializing two families of PTT (polytrimethyl terephthalate) polyesters made with bio-propanediol (bioPDO) produced by bacterial fermentation of cornstarch. The base resin contains up to 35% renewably sourced material. DuPont Packaging & Industrial Polymers is launching Biomax 1100 PTT for injection molded containers and cosmetic packaging. Performance is said to be similar to PBT and PET. It boasts good gloss, stiffness, strength, and colorability. It is resistant to common liquid formulas and is opaque to translucent in its natural state.

The bio-derived PTT base resin is also available as an engineering compound with 15% and 30% glass fiber, marketed as Sorona EP by DuPont Engineering Polymers. These contain 20% to 37% renewably sourced material and are said to have processing and properties similar to high-performance PBT. Early tests reportedly show improved surface appearance, lower warpage, and good dimensional stability. DuPont sees potential in automotive, electrical, and electronic parts.