Polylactic acid composites incorporating casein functionalized cellulose nanowhiskers

Journal of Biological Engineering

Jeffrey M Catchmark²  Jin Gu¹ 

[1] Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA 16802, USA;Department of Agricultural and Biological Engineering, The Pennsylvania State University, 109 Ag. Eng. Bldg., University Park, PA 16802, USA

关键词: Fluorescence microscopy;    Surface plasmon resonance;    Polylactic acid;    Whole milk casein;    Cellulose nanowhiskers;   

Others  :  821017
DOI  :  10.1186/1754-1611-7-31

 received in 2013-07-03, accepted in 2013-11-29,  发布年份 2013

【 摘 要 】

Background

Polylactic acid (PLA) is considered to be a sustainable alternative to petroleum-based polymers for many applications. Using cellulose fiber to reinforce PLA is of great interest recently due to its complete biodegradability and potential improvement of the mechanical performance. However, the dispersion of hydrophilic cellulose fibers in the hydrophobic polymer matrix is usually poor without using hazardous surfactants. The goal of this study was to develop homogenously dispersed cellulose nanowhisker (CNW) reinforced PLA composites using whole milk casein protein, which is an environmentally compatible dispersant.

Results

In this study, whole milk casein was chosen as a dispersant in the PLA-CNW system because of its potential to interact with the PLA matrix and cellulose. The affinity of casein to PLA was studied by surface plasmon resonance (SPR) imaging. CNWs were functionalized with casein and used as reinforcements to make PLA composites. Fluorescent staining of CNWs in the PLA matrix was implemented as a novel and simple way to analyze the dispersion of the reinforcements. The dispersion of CNWs in PLA was improved when casein was present. The mechanical properties of the composites were studied experimentally. Compared to pure PLA, the PLA composites had higher Young’s modulus. Casein (CS) functionalized CNW reinforced PLA (PLA-CS-CNW) at 2 wt% filler content maintained higher strain at break compared to normal CNW reinforced PLA (PLA-CNW). The Young’s modulus of PLA-CS-CNW composites was also higher than that of PLA-CNW composites at higher filler content. However, all composites exhibited lower strain at break and tensile strength at high filler content.

Conclusions

The presence of whole milk casein improved the dispersion of CNWs in the PLA matrix. The improved dispersion of CNWs provided higher modulus of the PLA composites at higher reinforcement loading and maintained the strain and stress at break of the composites at relatively low reinforcement loading. The affinity of the dispersant to PLA is important for the ultimate strength and stiffness of the composites.

【 授权许可】

   
2013 Gu and Catchmark; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Jonoobi M, Harun J, Mathew AP, Oksman K: Mechanical properties of cellulose nanofiber (CNF) reinforced polylactic acid (PLA) prepared by twin screw extrusion. Compos Sci Technol 2010, 70:1742-1747.
• [2]Samir MASA, Alloin F, Dufresne A: Review of recent research into cellulosic whiskers, their properties and their application in nanocomposite field. Biomacromolecules 2005, 6:612-626.
• [3]Moon RJ, Martini A, Nairn J, Simonsen J, Youngblood J: Cellulose nanomaterials review: structure, properties and nanocomposites. Chem Soc Rev 2011, 40:3941-3994.
• [4]Eichhorn SJ, Dufresne A, Aranguren M, Marcovich NE, Capadona JR, Rowan SJ, Weder C, Thielemans W, Roman M, Renneckar S, et al.: Review: current international research into cellulose nanofibres and nanocomposites. J Mater Sci 2010, 45:1-33.
• [5]Iwatake A, Nogi M, Yano H: Cellulose nanofiber-reinforced polylactic acid. Compos Sci Technol 2008, 68:2103-2106.
• [6]Kowalczyk M, Piorkowska E, Kulpinski P, Pracella M: Mechanical and thermal properties of PLA composites with cellulose nanofibers and standard size fibers. Compos Part a-Appl S 2011, 42:1509-1514.
• [7]Bondeson D, Oksman K: Dispersion and characteristics of surfactant modified cellulose whiskers nanocomposites. Compos Interface 2007, 14:617-630.
• [8]Kvien I, Tanem BS, Oksman K: Characterization of cellulose whiskers and their nanocomposites by atomic force and electron microscopy. Biomacromolecules 2005, 6:3160-3165.
• [9]Oksman K, Mathew AP, Bondeson D, Kvien I: Manufacturing process of cellulose whiskers/polylactic acid nanocomposites. Compos Sci Technol 2006, 66:2776-2784.
• [10]Petersson L, Kvien I, Oksman K: Structure and thermal properties of poly(lactic acid)/cellulose whiskers nanocomposite materials. Compos Sci Technol 2007, 67:2535-2544.
• [11]Frone AN, Berlioz S, Chailan JF, Panaitescu DM, Donescu D: Cellulose fiber-reinforced polylactic acid. Polym Composite 2011, 32:976-985.
• [12]Wang B, Sain M: The effect of chemically coated nanofiber reinforcement on biopolymer based nanocomposites. Bioresources 2007, 2:371-388.
• [13]Onwulate CI, Thomas AE, Cooke PH: Effects of biomass in polyethylene or polylactic acid composites. J Biobased Mater Bio 2009, 3:172-180.
• [14]McKenzie HA: Milk proteins: Chemistry and Molecular Biology. New York, London: Academic Press; 1970.
• [15]Horne DS: Casein structure, self-assembly and gelation. Curr Opin Colloid In 2002, 7:456-461.
• [16]Fox PF, McSweeney PLH: Advanced dairy chemistry. 3rd edition. New York, NY: Kluwer/Plenum; 2003.
• [17]Yang G, Zhang LN, Han HW, Zhou JP: Cellulose/casein blend membranes from NaOH/urea solution. J Appl Polym Sci 2001, 81:3260-3267.
• [18]Zhang LN, Yang G, Xiao L: Blend Membranes of Cellulose Cuoxam/Casein. J Membrane Sci 1995, 103:65-71.
• [19]Mears D, Catchmark JM: Quantification of casein and cellulose binding affinity. In ASABE annual meeting. Pittsburg, PA: ASABE; 2010.
• [20]Kiehna SE, Laughrey ZR, Waters ML: Evaluation of a carbohydrate-pi interaction in a peptide model system. Chem Commun 2007, 43:4026-4028.
• [21]Gu J, Catchmark JM: Interaction of casein functionalized cellulose whiskers with poly(lactic acid). In ASABE annual meeting. Louisville, KY: ASABE; 2011.
• [22]Liu Y, Guo R: The interaction between casein micelles and gold nanoparticles. J Colloid Interf Sci 2009, 332:265-269.
• [23]Nylander T, Wahlgren NM: Forces between adsorbed layers of beta-casein. Langmuir 1997, 13:6219-6225.
• [24]Ozeki T, Verma V, Uppalapati M, Suzuki Y, Nakamura M, Catchmark JM, Hancock WO: Surface-bound casein modulates the adsorption and activity of kinesin on SiO(2) surfaces. Biophys J 2009, 96:3305-3318.
• [25]Verma V, Hancock WO, Catchmark JM: The role of casein in supporting the operation of surface bound kinesin. J Biol Eng 2008, 2:14. BioMed Central Full Text
• [26]Smith EA, Thomas WD, Kiessling LL, Corn RM: Surface plasmon resonance imaging studies of protein-carbohydrate interactions. J Am Chem Soc 2003, 125:6140-6148.
• [27]Gu J, Catchmark JM, Kaiser EQ, Archibald DD: Quantification of cellulose nanowhiskers sulfate esterification levels. Carbohyd Polym 2013, 92:1809-1816.
• [28]Guo J, Catchmark JM: Surface area and porosity of acid hydrolyzed cellulose nanowhiskers and cellulose produced by Gluconacetobacter xylinus. Carbohyd Polym 2012, 87:1026-1037.
• [29]Samir MASA, Alloin F, Sanchez JY, El Kissi N, Dufresne A: Preparation of cellulose whiskers reinforced nanocomposites from an organic medium suspension. Macromolecules 2004, 37:1386-1393.
• [30]Mathew AP, Oksman K, Sain M: The effect of morphology and chemical characteristics of cellulose reinforcements on the crystallinity of polylactic acid. J Appl Polym Sci 2006, 101:300-310.
• [31]Zhang XQ, Espiritu M, Bilyk A, Kurniawan L: Morphological behaviour of poly(lactic acid) during hydrolytic degradation. Polym Degrad Stabil 2008, 93:1964-1970.
• [32]Dong SP, Roman M: Fluorescently labeled cellulose nanocrystals for bioimaging applications. J Am Chem Soc 2007, 129:13810-13811.
• [33]Mathew AP, Oksman K, Sain M: Mechanical properties of biodegradable composites from poly lactic acid (PLA) and microcrystalline cellulose (MCC). J Appl Polym Sci 2005, 97:2014-2025.
• [34]Ehrenstein G: Polymeric materials: structure-properties-applications. Cincinnati, Ohio: Hanser Publishers; 2001.
• [35]Cao N, Fu YH, He JH: Preparation and physical properties of soy protein isolate and gelatin composite films. Food Hydrocolloid 2007, 21:1153-1162.
• [36]Bondeson D, Mathew A, Oksman K: Optimization of the isolation of nanocrystals from microcrystalline cellulose by acid hydrolysis. Cellulose 2006, 13:171-180.
• [37]Bradford MM: A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 1976, 72:248-254.
• [38]Vaia B, Smiddy MA, Kelly AL, Huppertz T: Solvent-mediated disruption of bovine casein micelles at alkaline pH. J Agr Food Chem 2006, 54:8288-8293.