Solid-state Shear Pulverization Research Articles

Stabilization of Dispersed Phase to Static Coarsening: Polymer Blend Compatibilization via Solid-State Shear Pulverization

Stabilization of Dispersed Phase to Static Coarsening: Polymer Blend Compatibilization via Solid-State Shear Pulverization

Trace levels of mechanochemical effects in pulverized polyolefins

This research investigated the structural changes that occur on different polyethylene polymer systems as a result of a novel pulverization process called solid-state shear pulverization (S3P). High-density polyethylene, low-density polyethylene, and two forms of linear low-density polyethylene were run through a pulverizer under high shear conditions as well as low shear conditions. The physical properties were examined before and after the pulverization via melt index, melt rheology, GPC, and DSC, techniques. The low shear pulverization did not noticeably alter the physical properties of the polymers. In contrast, high shear pulverization did result in an increase in viscosity as observed by melt index and oscillatory shear experiments, although solid-state and bulk properties as observed by DSC and GPC were not affected. These results indicate that a small amount of mechanochemically induced changes occur as a result of the pulverization process, including incorporation of a small amount of long-chain branches randomly placed on a few of the polymer chains. No evidence of short-chain branching resulting from S3P processing was found in these systems. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 671–679, 2001

Trace levels of mechanochemical effects in pulverized polyolefins

This research investigated the structural changes that occur on different polyethylene polymer systems as a result of a novel pulverization process called solid-state shear pulverization (S3P). High-density polyethylene, low-density polyethylene, and two forms of linear low-density polyethylene were run through a pulverizer under high shear conditions as well as low shear conditions. The physical properties were examined before and after the pulverization via melt index, melt rheology, GPC, and DSC, techniques. The low shear pulverization did not noticeably alter the physical properties of the polymers. In contrast, high shear pulverization did result in an increase in viscosity as observed by melt index and oscillatory shear experiments, although solid-state and bulk properties as observed by DSC and GPC were not affected. These results indicate that a small amount of mechanochemically induced changes occur as a result of the pulverization process, including incorporation of a small amount of long-chain branches randomly placed on a few of the polymer chains. No evidence of short-chain branching resulting from S3P processing was found in these systems. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 671–679, 2001

A New Polymer Processing Technology for Polymer Blends with Unmatched Viscosity: Solid-State Shear Pulverization (S3P)

Abstract Solid-State Shear Pulverization (S3P) is a new polymer processing technology capable of efficient mixing blends with different component viscosities (which are unprocessable by conventional melt extrusion due to the phase separation). S3P sub ects polymers to compression and shear, resulting in fracture into a powder of various particle size and particle size distribution. S3P also allows modification of properties by compatibilization of ordinarily incompatible polymers without adding premade copolymers or conventional functional groups. Additionally, because S3P produces powder, it is suitable for a solid-state dispersion of pigments, curing agents, catalysts and other additives without melting (unlike conventional compounding). After reviewing the S3P concept, this paper discusses recent experimental data. The research focuses on mixing like polymers such as virgin polypropylene (PP) with unmatched viscosity, resulting in blends with improved processability and a significant increase in elongation at break. A comparison with a conventional melt mixing by twin-screw extrusion is provided to demonstrate uniqueness of S3P processing. An additional example involves the mixing of dissimilar, ordinarily incompatible polymers such as recycled high-density polyethylene (PE-HD), low-density polyethylene (PE-LD), PP, polystyrene (PS), and polyvinyl chloride (PVC) with very different viscosities. Once again, the S3P-made material exhibited exceptionally high elongation at break as compared with that of the conventionally melt-mixed blend.

Novel Strategy for Polymer Blend Compatibilization: Solid-State Shear Pulverization

ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication to the EditorNEXTNovel Strategy for Polymer Blend Compatibilization: Solid-State Shear PulverizationNaomi Furgiuele, Andrew H. Lebovitz, Klementina Khait, and John M. TorkelsonView Author Information Department of Chemical Engineering and Polymer Technology Center and Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208-3120 Cite this: Macromolecules 2000, 33, 2, 225–228Publication Date (Web):December 28, 1999Publication History Received23 March 1999Published online28 December 1999Published inissue 1 January 2000https://doi.org/10.1021/ma990434iCopyright © 2000 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1293Altmetric-Citations89LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (176 KB) Get e-AlertsSUBJECTS:Copolymers,Crystallinity,Homopolymers,Phase transitions,Polymers Get e-Alerts

Solid-State Shear Pulverization of Plastics: A Green Recycling Process

A novel process called solid-state shear pulverization (S3P) has been developed at Northwestern University to recycle single or commingled postconsumer or preconsumer polymeric waste without sorting by type or color. This continuous, one-step process converts shredded plastic or rubber waste into controlled-particle-size powder ranging from coarse (10 and 20 mesh) to fine (80 mesh) or ultrafine (200 mesh). As a result, the pulverization product is usable in applications ranging from direct injection molding without prior pelletization, to rotational molding, to use in protective and decorative powder coatings, as well as to blending with virgin resins and compounding with additives. Scanning electron microscopy reveals that the fine particles have a unique elongated shape that is attributed to the high shear conditions occurring during the pulverization process. Injection-molded parts made from the powder product of the S3P process have mechanical and physical properties comparable to or better than the properties resulting from direct conventional processing of recycled single or commingled plastics. In addition, the parts made from the powder product of the S3P process are uniform in color, whereas parts injection-molded from multicolored recycled feedstock without prior pulverization via the S3P process are streaked, re during their commercial applicability. The improved mixing achieved via the S3P process is often accompanied by scission of the carbon-chain backbone of the polymers involved, as revealed by the generation of free radicals during S3P processing, associated mechanochemistry, and modification of the melt flow rate of the polymers by the S3P process. The implications of this chain scission process for in situ compatibilization of commingled plastic waste via S3P processing are discussed.