Degradation of Wood Flour/Poly (Lactic Acid) Composites Reinforced by Coupling Agents and Organo-Montmorillonite in a Compost Test


  • Ru Liu
  • Jinzhen Cao
  • Liang Ou-Yang


Wood flour/poly (lactic acid) composite, degradation, coupling agent, organo-montmorillonite


To investigate the degradation properties of wood flour (WF)/poly (lactic acid) (PLA) composites modified with organo-montmorillonite (OMMT) and two types of coupling agents, namely, maleic anhydride grafted polypropylene (MAPP) and silane (γ-methacryloxypropyltrimethoxysilane, KH-570), pure PLA, OMMT/PLA, and WF/PLA composites were prepared with the hot-press molding method and tested in a compost test for 6 mo. After compost tests, samples were also characterized with scanning electron microscopy, Fourier transform infrared spectrum, and differential scanning calorimeter for further understanding. The results showed that 1) introducing WF and OMMT accelerated the degradability of PLA (after 5 mo, all composites were completely degraded, whereas the pure PLA control still had 4.78% residue); 2) the two types of coupling agents had opposite effects on degradation of WF/PLA composites (MAPP delayed the degradation process, whereas silane accelerated it); 3) silane and OMMT had a synergic effect on degradability, which was supported by the complete degradation of WF/PLA composites modified with both silane and OMMT in 4 mo; 4) after a 3-mo compost, many cracks or voids occurred on the surface of PLA, and this compost test also resulted in separated WF. Tm values of PLA and OMMT/PLA decreased and their crystallinity degrees increased, suggesting faster degradation of PLA with WF and OMMT loading.


Abdul Khalil HPS, Ismail H (2000) Effect of acetylation and coupling agent treatments upon biological degradation of plant fibre reinforced polyester composites. Polym Test 20(1):65-75.nBala P, Samantaray BK (2001) Effect of alkylammonium intercalated montmorillonite as filler on natural rubber. J Mater Sci Lett 20:563-564.nBengtsson M, Oksman K (2006) Silane crosslinked wood plastic composites: Processing and properties. Compos Sci Technol 66:2177-2186.nCheng FO, Mong TH, Jia RL (2003) The nucleating effect of montmorillonite on crystallization of PET/montmorillonite nanocomposites. J Polym Res 10:127-132.nde Jong SJ, Arias ER, Rijkers DTS, van Nostrum CF, Kettenes-van den Bosch JJ, Hennink WE (2001) New insights into the hydrolytic degradation of poly(lactic acid): Participation of the alcohol terminus. Polymer (Guildf) 42(7):2795-2802.nDikobe DG, Luyt AS (2010) Morphology and thermal properties of maleic anhydride grafted polypropylene/ethylene-vinyl acetate copolymer/wood powder blend composites. J Appl Polym Sci 116:3193-3201.nFischer EW, Sterzel HJ, Wegner G (1973) Investigation of the structure of solution grown crystals of lactide copolymers by means of chemical-reactions. Colloid Polym Sci 251(11):980-990.nFortunati E, Armentano I, Iannoni A, Barbale M, Zaccheo S, Scavone M, Visai L, Kenny JM (2012) New multifunctional poly(lactide acid) composites: Mechanical, antibacterial, and degradation properties. J Appl Polym Sci 124:87-98.nFukusima K, Abbate C, Tabuani D, Gennari M, Camino G (2009) Biodegradation of poly(lactic acid) and its nanocomposites. Polym Degrad Stabil 94:1646-1655.nFukuzaki H, Yoshida M, Asano M, Kumakura M (1989) Synthesis of copoly (D, L-lactic acid) with relative low molecular weight and in vitro degradation. Eur Polym J 25:1019-1026.nGattin R, Copinet A, Bertrand C, Couturier Y (2002) Biodegradation study of a starch and poly(lactic acid) co-extruded material in liquid, composting and inert mineral media. Int Biodeterior Biodegradation 50:25-31.nGeorge J, Sreekala MS, Thomas S (2001) A review on interface modification and characterization of natural fiber reinforced plastic composites. Polym Eng Sci 41(9):1471-1485.nGregorova A, Hrabalova M, Kovalcik R, Wimmer R (2011) Surface modification of spruce wood flour and effects on the dynamic fragility of PLA/wood composites. Polym Eng Sci 51:143-150.nHemmasi AH, Khademi-Eslam H, Talaiepoor M, Kord B, Ghasemi I (2010) Effect of nanoclay on the mechanical and morphological properties of wood polymer nanocomposite. J Reinf Plast Comp 29:964-971.nHuda MS, Drzal LT, Mohanty AK, Misra M (2006) Wood-fiber-reinforced poly (lactic acid) composites: Evaluation of the physicomechanical and morphological properties. J Appl Polym Sci 102:4856-4869.nInternational Organization for Standardization (2004) Plastics—Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test. ISO 20200:2004 [United Kingdom].nJiang XH, Cao JZ, Luo GQ (2011) Physical and mechanical properties of MMT/PVA/wood composites. Chemistry and Industry of Forest Products 31(1):41-46.nKolstad JJ (1996) Crystallization kinetics of poly (L-lactideco-meso-lactide). J Appl Polym Sci 62(7):1079-1091.nKulinski Z, Piorkowska E (2009) Crystallization, structure and properties of plasticized poly (L-lactide). Polymer (Guildf) 46:10290-10300.nLeBaron PC, Wang Z, Pinnavaia TJ (1999) Polymer-layered silicate nanocomposites: An overview. Appl Clay Sci 15:11-29.nLee SH, Wang S (2006) Biodegradable polymers/bamboo fiber biocomposite with bio based coupling agent. Compos, Part A Appl Sci Manuf 37:80-91.nLee SY, Kang IA, Doh GH, Kim WJ, Kim JS, Yoon HG, Wu Q (2008) Thermal, mechanical and morphological properties of polypropylene/clay/wood flour nanocomposites. Express Polym Lett 2:78-87.nLewitus D, McCarthy OA, Kenig S (2006) The effect of nanoclays on the properties of PLLA-modified polymers part 1: Mechanical and thermal properties. Journal of Polymers and the Environment 14:171-177.nLiu JW, Zhao Q, Wan CX (2001) Research progresses on degradation mechanism in vivo and medical applications of polylactic acid. Space Med Med Eng (Beijing) 14(4):308-312.nLiu LS, Fishman LM, Hicks BK, Liu AK (2005) Biodegradable composites from sugar beet pulp and poly(lactic acid). J Agric Food Chem 53:9017-9022.nLv WH, Zhao GJ, Xue ZH (2006) Preparation and characterization of wood/montmorillonite nanocomposites. For Stud China 8(1):35-40.nMarcovich NE, Villar MA (2003) Thermal and mechanical characterization of liner low density polyethylene/wood flour composites. J Appl Polym Sci 90(10):2775-2784.nMartin O, Averous L (2001) Poly (lactic acid): Plasticization and properties of biodegradable multiphase systems. Polymer (Guildf) 42:6209-6219.nMatuana LM (2009) Rigid PVC/(layered silicate) nanocomposites produced through a novel melt-blending approach. J Vinyl Addit Techn 10:77-86.nMatuana LM, Balatinecz JJ, Park CB, Sodhi RNS (1999) X-ray photoelectron spectroscopy study of silane-treated newsprint-fibers. Wood Sci Technol 33(4):259-270.nMatuana LM, Park CB, Balatinecz JJ (1998) Cell morphology and property relationships of microcellular foamed PVC/wood-fiber composites. Polym Eng Sci 38(11):1862-1872.nMeng QK, Hetzer M, De Kee D (2010) PLA/clay/wood nanocomposites: Nanoclay effects on mechanical and thermal properties. J Composite Mater 45(10): 1145-1158.nMobedi H, Mashak A, Nekoomanesh M, Orafai H (2011) L-lactide additive and in vitro degradation performance of poly(l-lactide) films. Iran Polym J 20:237-245.nMobedi H, Nekoomanesh M, Orafaei H, Mivehchi H (2006) Studying the degradation of poly(l-lactide) in presence of magnesium hydroxide. Iran Polym J 15:31-39.nMohanty AK, Misra M, Drzal LT (2001) Surface modifications of natural fibers and performance of the resulting biocomposites: An overview. Compos Interfaces 8(5):313-343.nNavarro M, Ginebra MP, Planell JA, Barrias CC, Barbosa MA (2005) In vitro degradation behavior of a novel bioresorbable composite material based on PLA and a soluble CaP glass. Acta Biomater 1:411-419.nNieddu E, Mazzucco L, Gentile P, Benko T, Balbo V, Mandrile R, Ciardelli G (2009) Preparation and biodegradation of clay composites of PLA. React Funct Polym 69:371-379.nNiu XF, Wang YL, Luo YF, Pan J, Shang JF, Guo LX (2005) Synthesis of the biomimetic polymer: Aliphatic diamine and RGDS modified poly (D, L-lactic acid). Chin Chem Lett 16(8):1035-1038.nOksman K (1996) Improved interaction between wood and synthetic polymers in wood/polymer composites. Wood Sci Technol 30:197-205.nPetinakis E, Liu X, Yu L, Way C, Sangwan P, Dean K, Bateman S, Edward G (2010) Biodegradation and thermal decomposition of poly(lactic acid)-based materials reinforced by hydrophilic fillers. Polym Degrad Stabil 95:1704-1707.nPetinakis E, Yu L, Edward G, Dean K, Liu H, Scully A (2009) Effect of matrix-particle interfacial adhesion on the mechanical properties of PLA/wood-flour microcomposites. Journal of Polymer and Environmental 17:83-94.nRay SS, Yamada K, Okamoto M, Ueda K (2003) New polylactide-layered silicate nanocomposites. 2. Concurrent improvements of material properties, biodegradability and melt rheology. Polymer (Guildf) 44:857-866.nReeve MS, McCarthy SP, Gross RA (1993) Preparation and characterization of (r)-poly (β-hydroxybutyrate)-poly (ε-capro-lactone) and (r)-poly(β-hydroxybutyrate)-poly (ε-lactide) degradable diblock copolymers. Macromolecules 26(5):888-894.nSain M, Suhara P, Law S, Bouilloux A (2005) Interface modification and mechanical properties of natural fiber-polyolefin composite products. J Reinf Plast Comp 24(2):121-130.nScheneider M (1994) Wood polymer composites. Wood Fiber Sci 26(1):142-151.nShih C (1995) Chain end scission in acid catalyzed hydrolysis of poly(D, L-lactide) in solution. J Control Release 34:9-15.nStandardization Administration of the People's Republic of China (2000) Plastics—Determination of flexural properties. GB/T 9341-2000. China.nTakatani M, Ikeda K, Sakamoto K, Okamoto T (2008) Cellulose esters as compatibilizers in wood/poly (lactic acid) composite. J Wood Sci 54:54-61.nThellen C, Orroth C, Froio D, Ziegler D, Lucciarini J (2005) Influence of montmorillonite layered silicate on plasticized poly (L-lactide) blown films. Polymer (Guildf) 46(25):11716-11727.nTsuji H, Tezuka Y (2005) Alkaline and enzymatic degradation of L-lactide copolymers, 1. Amorphous-made films of L-lactide copolymers with D-lactide, glycolide, and epsilon-caprolactone. Macromol Biosci 5(2):135-148.nWang L, Cao JZ, Jiang XH, Liu R (2010) Properties and characterization of poplar wood treated with the montmorillonite-DDAC compound preservative. Journal of Beijing Forestry Univeristy 32(4):242-246.nWang Y, Cao JZ, Zhu LZ (2011) Stress relaxation of wood flour/polypropylene composites at room temperature. Wood Fiber Sci 43(3):262-270.nZhao GJ, Lv WH (2003) Nanoscale in wood, nanowood and wood-inorganic nanocomposite. For Stud China 5(1):44-48.nZhong Y, Poloso T, Hetzer M, De Kee D (2007) Enhancement of wood/polyethylene composites via compatibilization and incorporation of organoclay particles. Polym Eng Sci 10:797-803.n






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