Cellulose nanoparticles as reinforcement and fillers in LDPE nanocomposites for production of low density packaging material

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dc.contributor.advisorChimphango, Annie Fabian Abelen_ZA
dc.contributor.advisorGreyling, Guilaumeen_ZA
dc.contributor.authorMdungazi, Seanen_ZA
dc.contributor.otherStellenbosch University. Faculty of Engineering. Dept. of Process Engineering.en_ZA
dc.date.accessioned2022-11-23T12:21:33Zen_ZA
dc.date.accessioned2023-01-16T12:53:46Zen_ZA
dc.date.available2022-11-23T12:21:33Zen_ZA
dc.date.available2023-01-16T12:53:46Zen_ZA
dc.date.issued2022-12en_ZA
dc.descriptionThesis (MEng) -- Stellenbosch University, 2022en_ZA
dc.description.abstractENGLISH ABSTRACT: Cellulose nanocrystals (CNC) have the potential to be used as reinforcement in petroleum-based polymers such as low-density polyethylene (LDPE) in the synthesis of LDPE nanocomposites. One of the challenges is the addition of the CNC in the LDPE form agglomerates. Therefore, surface modifications of the CNC such as acetylation and polyethylene adsorption may be utilized to reduce the agglomeration. However, these modifications have the potential to impact the cumulative energy demand (CED) and global warming potential (GWP) of the overall synthesis process. The study aimed to investigate the effect of acetylation and polyethylene adsorption of the CNC on the dispersion in LDPE, and on Young’s modulus, tensile strength, stress at break, water contact angle (WCA), moisture absorption, CED and GWP of the LDPE nanocomposites. The LDPE nanocomposites reinforced with acetylated cellulose nanocrystals (ACNC) were prepared by mixing LDPE with ACNC. The degree of substitution (DS) of the ACNC was varied (DS 1.19, 1.62, and 1.94) with CNC loading (1, 3, and 5 wt. %). Subsequently, the LDPE nanocomposites reinforced with polyethylene oxide (PEO) adsorbed cellulose nanocrystals (PEO-CNC) were developed by mixing the LDPE with PEO-CNC. The PEO:CNC dosage was varied (0.5:1, 1.5:1, and 2.5:1) with CNC loading (1, 3, and 5 wt. %). The nanocomposites were solvent cast (140 °C) and injection moulded (130 °C, 350 bar). The dispersion was described using Free-path spacing and characterization was done using field emission scanning electron microscopy (FE – SEM). The functional (mechanical and physical) properties were investigated using stress-strain curves, the sessile drop method, and a precision balance. The CED and GWP were estimated using a life cycle assessment conducted using OpenLCA software. The results showed that only CNC loading had a significant effect (p<0.05) on the dispersion (D0.1 %) of the LDPE nanocomposites reinforced with ACNC and PEO-CNC. The dispersion (D0.1 %) of the ACNC and PEO-CNC decreased from 8.81 - 4.19 % and from 7.97 – 6.96 % respectively with an increase in CNC loading (1 – 5 wt. %). DS had a significant effect (p<0.05) on Young’s modulus of the LDPE nanocomposites reinforced with ACNC. Young’s modulus increased from 181.95 – 217.2 MPa with an increase in DS (DS 1.19 – 1.94). The CNC loading had a significant effect (p<0.05) on the tensile strength of both nanocomposites. The tensile strength decreased from 26.2 – 25.9 MPa and 32.98 – 9.11 MPa with an increase in CNC loading (1 – 5 wt. %) for the LDPE nanocomposites reinforced with ACNC and PEO-CNC, respectively. The stress at break decreased from 50 - 14.75 % with an increase in CNC loading (1 – 5 wt. %) for the LDPE nanocomposites reinforced with PEO-CNC. The DS, PEO dosage, and CNC loading had no significant effect (p>0.05) on the WCA. The WCA decreased numerically from 89.7 – 88.5° and 76.3 – 71.5 ° with an increase in CNC loading (1 – 5 wt. %) for the LDPE nanocomposites reinforced with ACNC and PEO-CNC, respectively. The PEO dosage, DS, and CNC loading had no significant effect on moisture absorption (p>0.05). The moisture absorption increased numerically from 1.10 – 8.83 % and from 3.29 – 6.93 % with an increase in CNC loading (1- 5 wt. %) for the LDPE nanocomposites reinforced with ACNC and PEO-CNC, respectively. The PEO dosage, DS, and CNC loading had no significant effect (p>0.05) on the CED and the GWP. The cumulative energy demand (CED) increased numerically from 3119 - 4032 MJ and 3040 - 4304 MJ with an increase in CNC loading (1 – 5 wt. %) for LDPE nanocomposites reinforced with ACNC and PEO-CNC, respectively. The GWP increased numerically from 331 - 482 kg·CO2 and from 328 - 470 kg·CO2 with an increase in CNC loading (1 – 5 wt. %) for LDPE nanocomposites reinforced with ACNC and PEO-CNC, respectively. The findings of the study show that acetylation increased Young’s modulus of the LDPE nanocomposites while PEO adsorption decreased the functional properties of the LDPE nanocomposites. Both acetylation and PEO adsorption had no impact on the environmental impact of the LDPE nanocomposites. The functional properties and environmental impact were mainly dependent on the CNC loading.en_ZA
dc.description.abstractAFRIKAANS OPSOMMING: nanokristalle (CNC) het die potensiaal om gebruik te word as versterking in petroleum-gebaseerde polimere soos lae-digtheid poliëtileen (LDPE) in die sintese van LDPE-nanosamestelllings. Een van die uitdagings is dat die byvoeging van die CNC in die LDPE agglomerate vorm. Daarom kan die oppervlakmodifikasies van die CNC soos asetilering en poliëtileenadsorpsie gebruik word om die agglomerasie te verminder. Hierdie modifikasie het egter ’n potensiële impak op die kumulatiewe energie-aanvraag (CED) en globale verwarmingspotensiaal (GWP) van die algehele sinteseproses. Die studie beoog om die effek van asetilering en poliëtileenadsorpsie van die CNC op die verspreiding in LDPE te ondersoek, asook op Young se modulus, trekkrag, spanning by breek, waterkontakhoek (WCA), vogabsorpsie, CED en GWP van die LDPE-nanosamestellings. Die LDPE-nanosamestellings wat deur geasetileerde sellulose nanokristalle (ACNC) versterk is, is voorberei deur LDPE met ACNC te meng. Die grade van substitusie (DS) van die ACNC is gevarieer (DS 1.19, 1.62 en 1.94) met CNC-lading (1, 3, en 5 wt%). Gevolglik is die LDPE-nanosamestellings, versterk met poliëtileenoksied (PEO) sellulose wat nanokristalle (PEO-CNC) geadsorbeer het, ontwikkel deur die LDPE met PEO-CNC te meng. Die PEO:CNC-dosering is gevarieer (0.5:1, 1.5:1, en 2.5:1) met CNC-lading (1, 3, en 5 wt.%). Die nanosamestellings is oplosmiddel gegiet (140 °C) en gespuitvorm (130 °C, 350 bar). Die verspreiding is beskryf deur Free-path spasiëring en karakterisering is gedoen deur veldemissieskandering-elektronmikroskopie (FE-SEM). Die funksionele (meganiese en fisiese) eienskappe is ondersoek deur spanning-druk-kurwes, die sessiel-val-metode, en ’n presisiebalans. Die CED en GWP is beraam deur ’n lewensiklusanalise te gebruik in OpenLCA-sagteware. Die resultate het getoon dat slegs CNC-lading ’n beduidende effek (p<0.05) op die verspreiding (D0.1%) van die LDPE-nanosamestellings, versterk met ACNC en PEO-CNC, het. Die verspreiding (D0.1%) van die ACNC en PEO-CNC het afgeneem van 8.81 tot 4.19% en van 7.97 tot 6.96% onderskeidelik met ’n toename in CNC-lading (1 – 5 wt.%). DS het ’n beduidende effek (p<0.05) op Young se modulus gehad van die LDPE-nanosamestelling wat versterk is met ACNC. Young se modulus het verhoog van 181.95 tot 217.2 MPa met ’n verhoging in DS (DS 1.19 – 1.94). Die CNC-lading het ’n beduidende effek (p<0.05) op die trekkrag van beide nanosamestellings gehad. Die trekkrag het van 26.2 tot 25.9 MPa en 32.98 tot 9.11 MPa verminder met ’n verhoging in CNC-lading (1 – 5 wt.%) vir die LDPE-nanosamestellings versterk deur ACNC en PEO-CNC, onderskeidelik. Die spanning by breek het verminder van 50 tot 14.75% met ’n verhoging in CNC-lading (1 – 5 wt.%) vir die LDPE-nanosamestellings versterk met PEO- CNC. Die DS, PEO-dosering, en CNC-lading het geen beduidende effek (p>0.05) op die WCA gehad nie. Die WCA het numeries van 89.7 tot 88.5° en 76.3 tot 71.5° verlaag met ’n verhoging in CNC-lading (1 – 5 wt.%) vir die LDPE-nanosamestellings versterk met ACNC en PEO-CNC, onderskeidelik. Die PEO-dosering, DS en CNC-lading het geen beduidende effek op vogabsorpsie (p>0.05) gehad nie. Die vogabsorpsie het numeries van 1.10 tot 8.83% en van 3.29 tot 6.93% verhoog met ’n verhoging in CNC-lading (1 – 5 wt.%) vir die LDPE-nanosamestellings versterk met ACNC en PEO-CNC, onderskeidelik. Die PEO-dosering, DS, en CNC-lading het geen beduidende effek (p>0.05) op die CED en die GWP gehad nie. Die kumulatiewe energie-aanvraag (CED) het numeries verhoog van 3119 tot 4032 MJ en 3040 tot 4304 MJ met ’n verhoging in CNC-lading (1 – 5 wt.%) vir LDPE-nanosamestellings versterk met ACNC en PEO-CNC, onderskeidelik. Die GWP het numeries verhoog van 331 tot 482 kg·CO2 en van 328 tot 470 kg·CO2 met ’n verhoging in CNC-lading (1 – 5 wt.%) vir LDPE-nanosamestellings versterk met ACNC en PEO-CNC, onderskeidelik. Die bevindinge van hierdie studie wys dat asetilering Young se modulus van die LDPE-nanosamestellings verhoog het, terwyl PEO-adsorbsie die funksionele eienskappe van die LDPE-nanosamestellings verlaag het. Beide asetilering en PEO-adsorpsie het geen impak op die omgewingsimpak van LDPE-nanosamestellings gehad nie. Die funksionele eienskappe en omgewingsimpak was hoofsaaklik afhanklik van die CNC-lading.af_ZA
dc.description.versionMastersen_ZA
dc.identifier.urihttp://hdl.handle.net/10019.1/126172en_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subjectCelluloseen_ZA
dc.subjectPolyethylene -- Synthesisen_ZA
dc.subjectNanocomposites (Materials)en_ZA
dc.subjectUCTDen_ZA
dc.titleCellulose nanoparticles as reinforcement and fillers in LDPE nanocomposites for production of low density packaging materialen_ZA
dc.typeThesisen_ZA
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