Enhanced Polymer Properties by Solid State Shear Pulverization (28003
Northwestern’s solid state shear pulverization (S3P) process improves the physical properties of a variety of homopolymers. Enhanced polymer crystallinity, mechanical and oxygen barrier properties are achieved with S3P processing.ADVANTAGES: S3P polymer treatment significantly enhances polymer crystallinity, mechanical and oxygen barrier properties without the need of additive nucleating agents or fillers.
SUMMARY: Various solid-state processes have been applied to polymers, including ball milling, mechanical alloying, pan milling and solid-state shear pulverization to achieve intimate mixing of blends and nano-composites. Solid-state shear pulverization (S3P), a continuous process, has demonstrated intimate mixing and dispersion of immiscible polymer blends and appears well suited to industrial practice.
S3P treatment of one component homopolymers offers a novel means to enhance polymer properties. Thus S3P processing of a range of homopolymers including polyethylene (PP), low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), ε-caprolactone (PCL) and polyethylene terephthalate (PET) produces significant improvement in the resulting crystallinity, mechanical and oxygen barrier properties. No polymer degradation, as monitored by MW, occurs during processing in most cases. Isothermal crystallization half times are reduced 27-85% after processing (Table 1) and PET crystallinity increased from 13% to 32%. Mechanical strength was comparable or enhanced relative to unprocessed polymer in all cases examined (Figure 1). Finally, oxygen permability was reduced in these systems, particularly with treated PET and PCL (Figure 2). The polymer property improvements rival those obtained upon addition of nucleating agents, clays and fillers. Thus a potential industrial suited technique for homopolymer property improvement has been created.
STATUS: The process has been operated on pilot scale equipment and a patent has been filed.
Type of Offer: Licensing
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