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New compatibilizing agents for blends of linear low-density polyethylene and polystyrene as model systems of the post-consumer plastic waste stream

Li, Tao
http://rave.ohiolink.edu/etdc/view?acc_num=case1061478646

Abstract Details

1994, Doctor of Philosophy, Case Western Reserve University, Macromolecular Science.
In Chapters 1 and 2, the hierarchical morphology and mechanical properties of commingled plastic beams have been examined. Blends of recycled HDPE with virgin expanded polystyrene (VEPS) were compared with blends of a virgin HDPE (VHDPE). At the macroscale, the beams consisted of a solid skin and a voided core. At the microscale, blends of RHDPE and VHDPE exhibited a gradient morphology with highly elongated VEPS domains near the edge and spherical or co-continuous VEPS domains closer to the core. The flexural modulus was dominated by the properties of the skin. The compressive modulus was lower than the flexural modulus and was strongly affected by the skin-core macro-morphology. Flexural fracture initiated on the tension side of the beam and propagated rapidly through the thickness, while compressive failure occurred by longitudinal splitting of the skin. Chapter 3 deals morphology and modulus of LLDPE/PS (50/50) blends compatibilized with copolymers of styrene and butadiene (SB and SBS) and also with hydrogenated SB and SBS (SEB and SEBS). Compatibilization with SEB and SEBS led to fine dispersion of PS phase. Five percent compatibilizer could change the modulus of the blends by up to 50%. A morphous SB, SBS and SEBS lowered the modulus by as much as 50%. A model was developed to predict the modulus decrease by assuming that a certain percentage of the rubbery compatibilizer formed a shell around the dispersed PS particle. The increase in modulus by as much as 40% with crystalline SEB and SEBS was due to the crystallization of EB segments, which prevented formation of a rubbery shell. Tensile properties and microdeformation mechanisms of uncompatibilized LLDPE/PS and compatibilized LLDPE/PS (50/50) blends were also investigated (Chapter 4). Yield stress (σ Y), fracture stress (σ f) and fracture strain (varepsilon f) of LLDPE/PS blends decreased with PS content. Models were developed to predict the decrease of these properties by taking account of debonding and void around the PS particle. The largest increase by as much as 120% in σ Y and 145% in σ f of LLDPE/PS (50/50) blends was achieved by crystalline SEB and SEBS, which also significantly improved the blend toughness by as much as 7 times. Amorphous compatibilizers produced the largest increase in toughness by as much as 10 times and also increased σ Y and σ f by as much as 35% and 75%, respectively. High interfacial strength model was developed to predict the yield stress increase
Anne Hiltner (Advisor)
276 p.
Plastics Technology
Compatibilizing agents; Polyethylene and polystyrene; Plastic waste stream

Recommended Citations

Citations

  • Li, T. (1994). New compatibilizing agents for blends of linear low-density polyethylene and polystyrene as model systems of the post-consumer plastic waste stream [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1061478646

    APA Style (7th edition)

  • Li, Tao. New compatibilizing agents for blends of linear low-density polyethylene and polystyrene as model systems of the post-consumer plastic waste stream. 1994. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1061478646.

    MLA Style (8th edition)

  • Li, Tao. "New compatibilizing agents for blends of linear low-density polyethylene and polystyrene as model systems of the post-consumer plastic waste stream." Doctoral dissertation, Case Western Reserve University, 1994. http://rave.ohiolink.edu/etdc/view?acc_num=case1061478646

    Chicago Manual of Style (17th edition)

case1061478646
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© 1994, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.