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DeLeo, Candice Lee (2010) REACTIVELY COMPATIBILIZED STARCH-BASED RENEWABLE POLYMER BLENDS. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Starch-based polymeric materials offer a renewable, economical alternative to existingpetroleum based, non-renewable or costly biodegradable polymeric materials. We present thedevelopment and characterization of two phase blends of plasticized starch (PLS) andpolypropylene (PP) compatibilized via an interfacial chemical reaction. Starch is an abundant, naturally occurring polysaccharide that is obtained from variousplant sources. Having three hydroxyl groups per glucose monomer unit, starch is an inherentlymultifunctional polymer. When starch is blended with another polymer, such functionally can beused to reactively compatibilize the two phase system. We first examine the effects ofmultifunctional reactive compatibilization in model immiscible polymer blends and comparethem to compatibilization using diblock copolymers. We study the rheological andmorphological effects of the crosslinked interface and investigate the effects of varying thereactive compatibilizer concentration and the homopolymer loading. We next develop a processing methodology and conduct a systematic characterizationstudy of PLS and PP blends. Based on the result of our model blend study, multifunctionalreactive blending was employed using maleated polypropylene (MAPP). The maleic anhydridefunctional groups are able to react with hydroxyl functional starch, creating a compatibilizedsystem. The addition of layered silicate to the PLS/PP blends was employed to mitigate thedecline in mechanical properties as starch content increased. At sufficiently high plasticized starch loadings, the maleated polypropylene domainsacted as physical crosslinking sites. The processing, blending, compatibilization andcharacterization of plasticized starch resulted in a material with properties apt for severalelastomeric applications, such as rubber feet for electronic devices. The challenges of usingplasticized starch as an elastomer are also discussed. Lastly, we present a comparative life cycle assessment of plasticized starch andpolypropylene. The system boundary of this assessment is defined to be "cradle to gate" inwhich we analyze the system from raw material extraction to the final production of a polymerpellet.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
DeLeo, Candice Leecld46@pitt.eduCLD46
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairVelankar, Sachinvelankar@pitt.eduVELANKAR
Committee MemberYoung,
Committee MemberNettleship, Iannettles@pitt.eduNETTLES
Committee MemberEnick, Robertrme@pitt.eduRME
Committee MemberLittle, Stevensrlittle@pitt.eduSRLITTLE
Date: 30 September 2010
Date Type: Completion
Defense Date: 13 July 2010
Approval Date: 30 September 2010
Submission Date: 29 June 2010
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Institution: University of Pittsburgh
Schools and Programs: Swanson School of Engineering > Chemical Engineering
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: compatibilizers; polymer blends; renewable polymers; plasticized starch; rheology
Other ID:, etd-06292010-142235
Date Deposited: 10 Nov 2011 19:49
Last Modified: 15 Nov 2016 13:45


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