Effect of chain extension on the properties of PLA/TPS blends and film blowing processing

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Proceedings titleAnnual Technical Conference - ANTEC, Conference Proceedings
Conference69th Annual Technical Conference of the Society of Plastics Engineers 2011, ANTEC 2011, 1 May 2011 through 5 May 2011, Boston, MA
Pages247251; # of pages: 5
SubjectBlend morphology; Blend viscosities; Blown-films; Chain extenders; Chain extension; Compounding process; Devolatilization; Film blowing; High melt strengths; matrix; PLA; Sorbitol; Starch gelatinization; Thermoplastic starch; Twin screw extrusion; Elastomers; Engineers; Gelation; Glycerol; Plastic products; Plasticizers; Polystyrenes; Reinforced plastics; Scanning electron microscopy; Solvents; Styrene; Viscosity; Starch
AbstractIn this paper, the effect of a multifunctional epoxyacrylic-styrene copolymer on the properties of PLA/Thermoplastic Starch (PLA/TPS) blends was investigated and its effect on the processing of blown films was clarified. The PLA/TPS blends were prepared by twin-screw extrusion. The dry-starch and plasticizers were mixed together in the first half of the extruder to complete starch gelatinization. Water was removed by devolatilization at mid-extruder and the PLA matrix was mixed with the water-free TPS in the latter portion of the compounding process. The standard blends comprised 27%TPS in the PLA matrix. The TPS phase comprised 36% plasticizers in the form of glycerol and sorbitol mixtures. Oscillatory-shear rheology was used to monitor changes in blend viscosity. Scanning electron microscopy on microtomed and acid-etched samples was carried out to assess the blend morphology. It was found that the viscosity of the PLA/TPS blends was dramatically increased by adding a small amount of epoxy-based chain extender (CE). This is of great interest for film-blowing since this process requires materials with high melt strength. Film blowing trials on a lab-scale equipment showed that PLA/TPS film could be successfully blown when sufficient levels of chain-extenders were used.
Publication date
AffiliationNational Research Council Canada (NRC-CNRC); NRC Industrial Materials Institute (IMI-IMI)
Peer reviewedYes
NPARC number21271077
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Record identifier9e71d9b0-6660-48f1-95da-e188be159f77
Record created2014-03-24
Record modified2016-05-09
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