Overview of Wood Plastic Composites: Focusing on Use of Bio-based Plastics and Co-extrusion Technique

Borm June Kim 한국목재공학회 2014 목재공학 Vol.42 No.5

Wood filler is a porous and anisotropic material having different size, shape, and aspect ratio. The use of wood fillerssuch as wood particle, wood flour, and wood pulp in wood plastic composites (WPCs) are growing rapidly becausethese wood fillers give improved strength and stiffness to WPCs. However, the wood fillers have originally poorcompatibility with plastic matrix affecting the mechanical properties of WPCs. Therefore, to improve compatibility betweenwood and plastic, numbers of physical and chemical treatments were investigated. While the various treatmentsled to improved performances in WPC industries using petroleum-based plastics, full biodegradation is still issues dueto increased environmental concerns. Hence, bio-based plastics such as polylactide and polyhydroxybutyrate having biodegradablecharacteristics are being applied to WPCs, but relatively expensive prices of existing bio-based plasticsprevent further uses. As conventional processing methods, extrusion, injection, and compression moldings have beenused in WPC industries, but to apply WPCs to engineered or structural places, new processing methods should bedeveloped. As one system, co-extrusion technique was introduced to WPCs and the co-extruded WPCs havingcore-shell structures make the extended applications of WPCs possible.

친환경 난연제와 탈크를 첨가한 목재·플라스틱 복합재의 기계적, 열적, 형태학적 및 수분흡수 특성에 관한 연구

이단비,김범준 한국가구학회 2016 한국가구학회지 Vol.27 No.2

Wood plastic composite (WPC) is a green composite made of wood flour and thermoplastics to provide better performance by removing the defects of both wood and plastics. However, relatively low thermal stability and poor fire resistance of wood and plastics included in WPC have been still issues in using WPC as a building material for interior applications. This study investigated the effect of environmentally-friendly flame retardants (EFFRs) on the mechanical, thermal, morphological, and water absorption properties of wood flour (WF)/talc/polypropylene (PP) composites in comparison with neat PP. The whole EFFRs-filled WF/talc/PP composites showed higher values in flexural strength, flexural modulus, and impact strength compared to neat PP. In thermal properties, aluminum hydroxide (AH)-filled composite showed a 36 °C reduction in maximum thermal decomposition temperature (Tmax) compared to neat PP, but magnesium hydroxide (MH) played an important role in improving thermal stability of filled composite by showing the highest Tmax. From this research, it can be said that MH has potentials in reinforcing PP-based WPCs with improvement of thermal stability.

Performance of Wood-plastic Composites Manufactured from Postconsumer Plastics and Wood Waste under Coastal Weathering in Thailand

Chatree Homkhiew,Chainarong Srivabut,Surasit Rawangwong,Worapong Boonchouytan 한국섬유공학회 2022 Fibers and polymers Vol.23 No.9

The performance of wood-plastic composites (WPCs) under natural weathering needs to be further evaluated, inparticular their resistance to coastal weathering in tropical counties. Because the coastal weathering is sensitive to the risingacidity of the sea and changes in the frequency of storms. Thus, the effects of coastal weathering, post-consumer plastic types(plastic bags, straws, and cups), and wood waste (twigs) contents in the range of 40-60 wt% on the durability of WPCs wereinvestigated. The samples were prepared by a twin-screw extruder and a compression molding machine. The results revealedthat the increase of wood flour from 40 to 60 wt% into the plastic bag composites insignificantly rose (about 0.12 %) themelting temperature, but significantly decreased (about 23.8 %) the melting enthalpy of the un-weathered WPCs. Postconsumerplastic from straws exhibits higher lightness and discoloration than that from a bag and cup, the plastic bag showsthe lowest these values. All the mechanical properties of the post-consumer plastics and WPCs significantly (α=0.05) reducedin all cases after coastal weathering for 6 months. Overall, the post-consumer plastics from both the straw and cup presentedhigher mechanical properties than the virgin high-density polyethylene; however, the WPCs based on the plastic bag showedthe lowest loss in modulus of rupture, modulus of elasticity, and shear strength after coastal weathering for 6 months.

열가소성 Wood-Plastic Composites의 기계적 물성에 미치는 커플링제의 영향

윤태호,신경섭,황택성,이존태 공주대학교 자원재활용 신소재 연구센터 1999 1차년도 센터 성과집 Vol.1999 No.-

목분 충진제의 함량을 달리 하고 PE수지를 매티릭스로 하여 wood plastic composites(WPC)를 제조하였다. 또한 매트릭스와 충진제간의 계면결합력을 증가시키기 위하여 커플링제로 phthalic anhydride(PA)를 사용하였으며, 충진제의 충진률과 커플링제 처리가 복합재의 기계적 물성에 미치는 영향과 계면현상을 관찰하였다. 목분의 충진률 30wt%, PA커플링제농도 3wt%일 때 인장강도는 26.37MPa로 최대값을 나타내었으며, 이때 충격강도는 46.24J/m의 최대값을 나타냈다. 또한 WPC는 주사전자현미경 관찰을 통해서 커플링제의 처리농도의 증가에 따라 목분과 PE 수지와의 분산과 결합이 잘 이루어졌으을 확인할 수 있었다. Wood powder as reinforcing fillers and polyethylene as a matrix have been used for wood plastic composites(WPC). In preparing WPC, the coupling agent, phthalic anhy dride(PA) was used in order to increase the interfacial bonding force between matrix and fillers. In this study, the effect of wood powder, PA concentration on the mechanical properties and interfcial phenomena on the composites was eveluated. The tensile strength of 3wt% PA-treated composites reached its maximum value of 25.91 MPa when the wood powder content was 30wt%, and the mximum impact strength of PA-treated composites was 46.24H/m. SEM observation showed that wood powder was well dispersed and bonded well with PE matrix by increasing the coupling agent concentration.

Study on Rapid Measurement of Wood Powder Concentration of Wood-Plastic Composites using FT-NIR and FT-IR Spectroscopy Techniques

Byoung Kwan Cho,Santosh Lohoumi,Chul Choi,Seong Min Yang,Seog Goo Kang 한국목재공학회 2016 목재공학 Vol.44 No.6

Wood-plastic composite (WPC) is a promising and sustainable material, and refers to a combination of wood and plastic along with some binding (adhesive) materials. In comparison to pure wood material, WPCs are in general have advantages of being cost effective, high durability, moisture resistance, and microbial resistance. The properties of WPCs come directly from the concentration of different components in composite; such as wood flour concentration directly affect mechanical and physical properties of WPCs. In this study, wood powder concentration in WPC was determined by Fourier transform near-infrared (FT-NIR) and Fourier transform infrared (FT-IR) spectroscopy. The reflectance spectra from WPC in both powdered and tableted form with five different concentrations of wood powder were collected and preprocessed to remove noise caused by several factors. To correlate the collected spectra with wood powder concentration, multivariate calibration method of partial least squares (PLS) was applied. During validation with an independent set of samples, good correlations with reference values were demonstrated for both FT-NIR and FT-IR data sets. In addition, high coefficient of determination (R2 p) and lower standard error of prediction (SEP) was yielded for tableted WPC than powdered WPC. The combination of FT-NIR and FT-IR spectral region was also studied. The results presented here showed that the use of both zones improved the determination accuracy for powdered WPC; however, no improvement in prediction result was achieved for tableted WPCs. The results obtained suggest that these spectroscopic techniques are a useful tool for fast and nondestructive determination of wood concentration in WPCs and have potential to replace conventional methods.

Wood Flour 폴리프로필렌 복합재료의 기계적 특성: 반복적 온도 변화의 영향

이선영 ( S. Y. Lee ),전상진 ( S. J. Chun ),도금현 ( G. H. Doh ),박상범 ( S. B. Park ),최수임 ( S. I. Choi ) 한국고무학회 2011 엘라스토머 및 콤포지트 Vol.46 No.3

본 연구에서는 반복적인 온도변화가 목분(50 wt.%와 70 wt.%)이 첨가된 폴리프로필렌 WPC(Wood Plastic Composites)의 기계적 특성에 미치는 영향을 조사하였다. WPC의 휨탄성계수(flexural modulus)와 휨강도(flexural strength)는 반복 회수에 상관없이 동결·융해 시험에서 계면접착력의 약화 때문에 감소하는 경향을 보였다. 목분의 함량이 높을 때, 휨탄성계수의 감소가 비교적 높았다. WPC의 휨탄성계수와 휨강도는 고온(60 ℃)·저온(-20 ℃) 반복시험 후 고온에서 감소하고 저온에서 증가되었다. 폴리프로필렌(polypropylene, PP)의 유리전이점(glass transition temperature: -10 ℃) 보다 낮은 저온(-20 ℃)에서 WPC는 높은 강성(stiffness)과 강도(strength)를 유발시키는 유리상태(glassy state)로 존재한다. 고온에서 목분의 함량이 낮은 WPC가 연성의 증가 때문에 낮은 휨탄성계수와 휨강도를 보였다. The effect of cycled temperature change on the mechanical properties of wood flour(50 wt.% and 70 wt.%) polypropylene WPC(Wood Plastic Composites) was investigated in this study. Flexural modulus and flexural strength of the WPC showed a decrease due to the degradation of interfacial adhesion between polymer matrix and wood flour by the freeze-thaw test regardless of the cycled number. At the higher loading level of wood flour, the reduction of the flexural modulus was remarkable. After the cycled heat-freeze test, it was found that the flexural modulus and flexural strength of the WPC were lower at the high temperature (60 ℃) and higher at the low temperature (-20 ℃). At the low temperature (-20 ℃) which is below glass transition temperature of polypropylene (-10 ℃), WPC is in a glassy state which brings about the high stiffness and strength. At the high temperature (60 ℃), the flexural modulus and flexural strength of the WPC with 50 wt.% wood flour were lower because of the increase of polymer ductility.

플라즈마 처리가 목분/폴리프로필렌 복합재의 계면에 미치는 영향 연구

하종록 ( Jong Rok Ha ),김병선 ( Byung Sun Kim ),이진우 ( Jin Woo Yi ) 한국복합재료학회 2013 Composites research Vol.26 No.3

상온·상압 플라즈마 표면처리된 목분을 폴리프로필렌(polypropylene)과 혼합하였을 때 두 재료의 계면에 미치는 영향을 연구하였다. 목분과 폴리프로필렌을 압출기를 통해 기계적으로 혼합한 후 사출기를 이용하여 목분함유량 50 wt% 목분/폴리프로필렌(Wood Plastic Composite, WPC) 복합재를 제조하였다. 플라즈마 표면처리 공정에 가장 적합한 Monomer(모노머)를 찾기 위해 Oxygen, Benzene, CH-4, Acrylic-acid, Hexafluoroethane, Trifluorotolune, Hexamethyl-disiloxane(HMDSO) 등 7가지의 모노머에 대해 Contact angle(접촉각)을 측정하여 표면에너지를 계산 하였다. 그 결과 HMDSO가 가장 높은 표면에너지를 나타내어 플라즈마 공정의 모노머로 적용하였다. 소수성인 폴리프로필렌과 친수성인 목분을 플라즈마 표면처리를 통하여 목분의 표면을 개질하였고 두 재료의 계면 결합력을 향상시킬 수 있었다. 기계적 물성평가 결과는 인장강도의 경우 최대 7.59%, 굴곡강도의 경우 최대 12.43%가 증가하였다. SEM(Scanning Electron Microscope)을 이용하여 파단면을 관찰하였고 플라즈마 표면처리의 효과를 확인하였다. Atmospheric glow plasma polymerization was applied to wood powder before fabricating polypropylene (PP) matrix composites. Seven different types of monomers (Oxygen, Benzene, CH4, Acrylic-acid, Hexafluoroethane, Trifluorotolune, Hexamethyl-disiloxane) were analyzed to determine the most suitable precursor for plasma polymerization. The surface energy was calculated from measured contact angle about each monomer on PP. Hexamethyl-disiloxane (HMDSO) had a highest surface energy and is selected as the most suitable monomer. Wood powder and polypropylene were mixed as pellets by twin screw extruder and then 50 wt% wood powder/PP composites were produced by an injection machine. Tensile strength and Flexural strength have improved by 7.59% and 12.43% at the maximum respectively. SEM (Scanning Electron Microscope) observation on the fracture surface revealed that the plasma polymerization have improved the interfacial bonding and the mechanical properties of the composites.

합성목재의 연소특성에 관한 연구

신백우 ( Baeg Woo Shin ),송영호 ( Young Ho Song ),이동호 ( Dong Ho Rie ),정국삼 ( Kook Sam Chung ) 충북대학교 산업과학기술연구소 2012 산업과학기술연구 논문집 Vol.26 No.1

주거 건축 및 가구산업의 자재로써 합성목재(Wood-Plastic Composites)는 점차 각광받고 있다. 본 연구에서는 합성목재의 연소특성을 살펴보기 위하여 한계산소지수 측정(ASTM D 2863) 및 콘칼로리미터 시험(ISO 5660-1)을 실시하였으며 또한 일반목재인 적송과 방부 처리를 한 방부목에 대하여도 동일한 시험을 통하여 합성목재와의 연소특성을 비교·검토하였다. 한계산소지수 측정결과 합성목재가 적송 및 방부목에 비해 낮게 측정되었다. 콘칼로리미터 시험결과 합성목재의 열방출률이 가장 높았고 또한, 최대 열방출률 및 평균 열방출률, 총 방출열량도 적송 및 방부목에 비해 높게 나타났다. Wood-Plastic Composites (WPCs) are one of spotlighting materials for the residential construction and the industry for furniture. At this study, the limiting oxygen index (LOI) was measured by ASTMD 2963 and the cone calorimeter test was done by ISO 5660-1 to find the combustion characteristics of WPCs. In addition, the identical test was implemented to compare the combustion characteritics between the red pine and the antiseptic wood. The result of LOI measurement showed that the LOI of WPCs was lower than that of red pine or antiseptic and the peak HRR as well as the average HRR and total heat release of WPCs was higher than those of red pine of antiseptized wood

Physical and Mechanical Properties of Wood-Plastic Composites Made with Microfibrillar Blends of LDPE, HDPE and PET

Seyyedeh Tahereh Mosavi-Mirkolaei,Saeed Kazemi Najafi,Mehdi Tajvidi 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10

The effect of microfibrillar blends of recycled plastics on selected physical and mechanical characteristics ofwood-plastic composites (WPCs) was investigated in this study. The production of wood plastic composites was carried outthrough a two-step extrusion technique. The plastic blends were drawn after extrusion to obtain microfibrillar morphology. The addition of polyethylene-co-glycidyl methacrylate (E-GMA) enhanced compatibility between the two phases and ahomogenous structure was seen in the fracture surfaces by scanning electron microscopy (SEM). The crystallinity of basepolymers increased with the addition of polyethylene terephthalate (PET) microfibrils, E-GMA and wood flour. The X-raydiffraction (XRD) patterns were also used to determine the crystallinity of all samples. According to the XRD results, thecrystallinity degree of recycled plastics was higher than that of virgin plastics. E-GMA improved the water resistance ofwood-plastic composites. The mechanical properties of samples were improved with the addition of PET microfibrils. Themicrofibrillar blending technique was found to be an effective approach for the production of high quality WPCs fromrecycled plastic blends.

팽창성 흑연과 금속수산화물이 목재⋅플라스틱 복합재의 특성에 미치는 영향에 관한 연구

김승균,이단비,이선영,전상진,김범준 한국가구학회 2016 한국가구학회지 Vol.27 No.4

Wood-plastic composites (WPCs) composed of mainly wood flour and thermoplastics have attracted considerable attentions due to advantages of cost effectiveness, high durability, and microbial resistance. However, relatively poor fire resistance of WPCs from low thermal stability of wood and plastics prevents further uses. This study investigated the effect of expandable graphite (EG) and aluminium hydroxide (AH)/magnesium hydroxide (MH) on the properties of WPCs. The combined incorporation of both EG and metal hydroxide (i.e., AH or MH) into formulations leads to higher flexural modulus of filled composites compared to neat PP and WPC. In thermal properties, EG played an important role in improving thermal stability of filled composites by suppressing thermal decompositions of wood and PP. Moreover, EG showed better water absorption features. From this research, it can be said that EG and metal hydroxides have potentials as effective reinforcement, flame retardant, and moisture barrier.