Isotactic polypropylene (iPP) is intrinsically brittle under fast load or at low temperatures, limiting its use as a high-performance engineering plastic. Past attempts to improve toughness through compounding or blending with rubber have been most effective at high rubber content (>20 wt%) which significantly reduces other mechanical properties and optical clarity of the final material. This new technology imparts toughness while maintaining desired mechanical properties and optical clarity. Low concentrations of hydrogenated styrene/butadiene diblock copolymer are added to the isotactic polypropylene to improve toughness. By simply melt-blending these copolymer agents with iPP, impact strength and toughness of the blend dramatically improves. Because the diblock copolymers are rubbery in nature and designed to disperse into 200-500 nm droplets during melt blending, increased toughness can be achieved with low loadings (5-10% wt%), preserving high clarity and strength. Dispersion of copolymer droplets in the iPP matrix does not substantially increase melt viscosity so the modified iPP retains molding and melt blowing ability. At the same time, clarity of the modified iPP is retained because the copolymer is not melt blended into the iPP matrix. This technology could offer a new toughening agent for commercial iPP applications that require high impact strength.
Primary Application Area: Materials, Chemical
Technology Development Status: Prototype
Technology Readiness Level: TRL 3
Organization Type: Academic/Gov Lab
Showcase Booth #: 109
GOVT/EXTERNAL FUNDING SOURCES
External Funding to Date: Grant