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1.
Untreated kenaf (KNF) and eco-friendly coupling agent (EFCA)-treated kenaf were used as filler to prepare natural fiber-reinforced polymer composites (NFPCs) using linear low-density polyethylene (LLDPE) and poly(vinyl alcohol) (PVOH) as polymer matrices. The composites containing various loadings of untreated and EFCA-treated KNF (0, 10, 20, and 40 phr) were melt-blended in an internal mixer. The effect of treatment on the behavior of processing torque, mechanical properties, morphology, functional groups, water absorption, and thermal stability of KNF/LLDPE/PVOH composites were investigated. The results revealed that EFCA-treated KNF composites exhibited higher equilibrium torque, indicating that the viscosity of molten composites increased in the presence of EFCA. The tensile strength and tensile modulus of KNF/LLDPE/PVOH composites were improved with the addition of EFCA-treated KNF attributed to the enhancement of the interfacial adhesion between KNF and LLDPE/PVOH matrices, as confirmed by field-emission scanning electron microscopy. Fourier transform infrared spectroscopy indicated the presence of ester bond in EFCA-treated KNF composites. Furthermore, EFCA-treated KNF composites possessed a lower water absorption and greater thermal stability as compared to untreated KNF composites. Therefore, EFCA could be suggested as an effective coupling agent to enhance the performance of KNF/LLDPE/PVOH composites.  相似文献   

2.
We explored the environmental aging behavior of banana‐fiber‐reinforced phenol formaldehyde (PF) composites. The composites were subjected to water aging, thermal aging, soil burial, and outdoor weathering. The effects of chemical modification and hybridization with glass fibers on the degradability of the composites in different environments were analyzed. The extent of degradation was measured by changes in the weight and tensile properties after aging. Absorbed water increased the weight of water‐aged composites, and chemical treatments and hybridization decreased water absorption. The tensile strength and modulus of the banana/PF composites were increased by water aging, whereas the strength and modulus of the glass/PF composites were decreased by water aging. As the glass‐fiber loading was increased in the hybrid composites, the increase in strength by water aging was reduced, and at higher glass‐fiber loadings, a decrease in strength was observed. The tensile properties of the composites were increased by oven aging. The percentage weight loss was higher for soil‐aged samples than for samples weathered outdoors. The weight loss and tensile strength of the glass/PF composites and banana/glass/hybrid/PF composites were much lower than those of the banana/PF composites. Silane treatment, NaOH treatment, and acetylation improved the resistance of the banana/PF composites on outdoor exposure and soil burial. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2521–2531, 2006  相似文献   

3.
The properties of polypropylene/(waste tire dust)/kenaf (PP/WTD/KNF) composites with the addition of phthalic anhydride (PA) as a function of KNF loading were studied. Composites containing constant PP and WTD compositions of 70 and 30 parts by weight per hundred parts of resin (phr), with various KNF loadings (0, 5, 10, 15, and 20 phr), were prepared by using a Thermo‐Haake Polydrive internal mixer at a temperature of 180°C with a rotor speed of 50 rpm. The results showed that tensile strength and elongation at break decreased, while tensile modulus, stabilization torque, water absorption, and thermal stability increased with increased KNF loading. PP/WTD/KNF composites with PA showed higher tensile strength, tensile modulus, and water uptake but lower stabilization torque and elongation at break when compared with PP/WTD/KNF composites. Scanning electron microscopy morphological study on the tensile fractured surface proves that the interfacial adhesion between PP/WTD and KNF was enhanced with the addition of PA. J. VINYL ADDIT. TECHNOL., 20:193–200, 2014. © 2014 Society of Plastics Engineers  相似文献   

4.
The objective of this study was to investigate the degradability of linear low‐density polyethylene (LLDPE)/(soya powder) blends. The blends were compatibilized by epoxidized natural rubber with 50 mol% of epoxidation. They were exposed to a natural compost medium located in northern Malaysia. The degradability was evaluated by using tensile tests, a morphological study, carbonyl indices, crystallinity measurements, weight loss, and molecular‐weight changes. The tensile strength and elongation at break of the compatibilized blends decreased during one year of exposure. The colonization of fungus and the formation of pores were observed in micrographs. The carbonyl indices, crystallinity, and weight loss increased during exposure, thereby indicating the degradation of the blends. The reduction in molecular weight revealed the degradation of the LLDPE upon composting. Surprisingly, after composting, the compatibilized blends showed more degradation than the uncompatibilized ones. J. VINYL ADDIT. TECHNOL., 20:42–48, 2014. © 2014 Society of Plastics Engineers  相似文献   

5.
Kenaf (KNF)‐filled polypropylene/waste tire dust (PP/WTD) composites containing different KNF loadings (0, 5, 10, 15, and 20 parts per hundred parts of resin (phr)) were prepared using a Thermo Haake Polydrive internal mixer. The influence of the KNF form (KNF short fiber (KNFs) and KNF powder (KNFp)) at different KNF loadings on properties of the composites was studied. Results showed that with increasing KNF loading, the stabilization torque, tensile modulus, water absorption, and thermal properties increased for both KNFp‐ and KNFs‐filled PP/WTD composites. However, the tensile strength and elongation at break decreased by 29.2% and 53.9%, respectively, for KNFp‐filled PP/WTD composites, whereas KNFs‐filled PP/WTD composites showed a decrement of 24.5% and 63.5%, respectively. The stabilization torque, tensile strength, and tensile modulus increased by 22.4%, 6.7%, and 2.6%, respectively, for KNFs‐filled PP/WTD composites at 20 phr KNF loading. The scanning electron microscopy morphological studies on the tensile fractured surfaces revealed poor adhesion between KNFp and PP/WTD matrices as compared to KNFs and PP/WTD matrices. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40877.  相似文献   

6.
Bamboo fiber (BF)-reinforced starch/polypropylene (PP) composites were prepared by extrusion and injection molding methods. The mechanical and thermal properties and water absorption were evaluated by different methods. Moreover, composite samples were subjected to biodegradation through soil burial test and microbes medium degradation. Different stages of biodegradation were investigated by weight loss, attenuated total reflection Fourier transformed infrared spectroscopy, differential scanning calorimeter, and scanning electron microscope. It was found that contents of BF and starch resin had a significant influence on the properties of the composites. With more content of BF, the composite exhibited a better flexural property and biodegradation. A distinct decrease of weight loss and mechanical properties indicated the degradation caused by the microbes. After biodegradation, thermal stability of the composites decreased while the crystallinity of PP increased. The results prove that the composites more easily tend to be degraded and assimilated by microbes. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 137, 48694.  相似文献   

7.
《国际聚合物材料杂志》2012,61(14):1065-1078
Polyvinyl alcohol (PVOH) with corn starch (CS) at 70/30 weight percent ratio were prepared by a solution casting method with the addition of attapulgite at a range of 0.0–1.0 grams. The aim of this study is to investigate the effect of attapulgite on biodegradability and tensile properties of PVOH/CS matrix. All the results were compared with the control sample (PVOH/CS). The presence of attapulgite had hindered the degradation process in enzymatic, soil, and compost burial. The water sorption content increased with increasing immersion time. The highest tensile strength and elongation at break were shown by the PVOH/CS with 0.2 g of attapulgite content.  相似文献   

8.
Linear low‐density polyethylene (LLDPE) was blended with decanol‐esterified styrene maleic anhydride copolymer (MDESMA) with an aim to enhance the environmental degradability of polyethylenes. Styrene‐maleic anhydride copolymer (SMA) was synthesized by precipitation polymerization, using benzoyl peroxide (BPO) as initiator. SMA was esterified with a long‐chain monoalcohol, n‐decanol, using methyl ethyl ketone (MEK) as solvent at 80°C to obtain monoesterified styrene‐maleic anhydride (MDESMA). Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA) were performed to characterize SMA and MDESMA. IR spectra of MDESMA showed a decrease in intensity of peak responsible for carbonyl absorption of a five‐membered ring anhydride group along with broadening of carboxyl O? H stretching peak. TGA showed two‐stage degradation for SMA and MDESMA. LLDPE was blended with MDESMA in single‐screw extruder and blends were characterized thermally by DSC and TGA. A single endothermic melting peak of LLDPE/MDESMA blend was observed. Films of the blends, formed by compression molding, showed an increase in modulus of elasticity but a decrease in elongation at break with increasing concentration of MDESMA. LLDPE/MDESMA blend compositions when kept in phosphate/citric acid buffer solution (pH ~ 8) showed initial weight gain because of water absorption and subsequently loss in weight due to dissolution of soluble component of blends. Film samples of blends kept for soil burial also showed similar behavior. Contact‐angle measurement of film samples of the blends showed an increase in value on soil burial, indicating degradation/dissolution of MDESMA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 102–108, 2004  相似文献   

9.
In this study, the degradability of linear low‐density polyethylene (LLDPE) and poly(L ‐lactic acid) (PLLA) blend films under controlled composting conditions was investigated according to modified ASTM D 5338 (2003). Differential scanning calorimetry, X‐ray diffraction, and Fourier transform infrared spectroscopy were used to determine the thermal and morphological properties of the plastic films. LLDPE 80 (80 wt % LLDPE and 20 wt % PLLA) degraded faster than grafted low‐density polyethylene–maleic anhydride (M‐g‐L) 80/4 (80 wt % LLDPE, 20 wt % PLLA, and 4 phr compatibilizer) and pure LLDPE (LLDPE 100). The mechanical properties and weight changes were determined after composting. The tensile strength of LLDPE 100, LLDPE 80, and M‐g‐L 80/4 decreased by 20, 54, and 35%, respectively. The films, as a result of degradation, exhibited a decrease in their mass. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

10.
A series of biodegradable polymer films based on poly(vinyl alcohol) (PVOH) and jackfruit waste flour (JWF) was prepared in the presence of water and glycerol and cast by a solution casting method. The JWF was introduced as a promoter of biodegradability. The blended films were evaluated for their tensile properties, water absorption, water vapor transmission rate (WVTR), and degradation behavior under different environmental conditions such as natural weathering and natural soil. The tensile strength (1.7–6.4 MPa) and elongation at break (13–108%) of the PVOH/JWF films were lower than those of unfilled PVOH film (26MPa and 238%). However, the Young's modulus values (157–196 MPa) of the PVOH/JWF films were higher than that of unfilled PVOH film (137 MPa). The PVOH/JWF blended films showed higher water absorption and WVTR, which increased with increasing JWF content. Biodegradability tests revealed that the presence of JWF stimulated the degradation rate and caused the weight loss and reduction in tensile properties of the PVOH/JWF blended films. J. VINYL ADDIT. TECHNOL., 2011. © 2011 Society of Plastics Engineers  相似文献   

11.
Increasing amounts of plastic waste in the environment have become a problem of gigantic proportions. The case of linear low‐density polyethylene (LLDPE) is especially significant as it is widely used for packaging and other applications. This synthetic polymer is normally not biodegradable until it is degraded into low molecular mass fragments that can be assimilated by microorganisms. Blends of nonbiodegradable polymers and biodegradable commercial polymers such as poly (vinyl alcohol) (PVA) can facilitate a reduction in the volume of plastic waste when they undergo partial degradation. Further, the remaining fragments stand a greater chance of undergoing biodegradation in a much shorter span of time. In this investigation, LLDPE was blended with different proportions of PVA (5–30%) in a torque rheometer. Mechanical, thermal, and biodegradation studies were carried out on the blends. The biodegradability of LLDPE/PVA blends has been studied in two environments: (1) in a culture medium containing Vibrio sp. and (2) soil environment, both over a period of 15 weeks. Blends exposed to culture medium degraded more than that exposed to soil environment. Changes in various properties of LLDPE/PVA blends before and after degradation were monitored using Fourier transform infrared spectroscopy, a differential scanning calorimeter (DSC) for crystallinity, and scanning electron microscope (SEM) for surface morphology among other things. Percentage crystallinity decreased as the PVA content increased and biodegradation resulted in an increase of crystallinity in LLDPE/PVA blends. The results prove that partial biodegradation of the blends has occurred holding promise for an eventual biodegradable product. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

12.
《Polymer Composites》2017,38(12):2841-2851
This work sought to improve the toughness and thermal stability of poly(lactic acid) (PLA) by incorporating poly(butylene succinate) (PBS) and wood flour (WF). The PLA/PBS blends showed a PBS‐dose‐dependent increase in the impact strength, elongation at break, degree of crystallinity, and thermal stability compared to the PLA, but the tensile strength, Young's modulus, and flexural strength were all decreased with increasing PBS content. Based on the optimum impact strength and elongation at break, the 70/30 (w/w) PLA/PBS blend was selected for preparing composites with five loadings of WF (5–30 phr). The impact strength, tensile strength, flexural strength, and thermal stability of the PLA/PBS/WF composites decreased with increasing WF content, and the degree of crystallinity was slightly increased compared to the 70/30 (w/w) PLA/PBS blend. Based on differential scanning calorimetry, the inclusion of PBS and WF into PLA did not significantly change the glass transition and melting temperatures of PLA in the PLA/PBS blends and PLA/PBS/WF composites. From the observed cold crystallization temperature of PLA in the samples, it was evident that the degree of crystallinity of PLA in all the blends and composites was higher than that of PLA. The PLA/PBS blend and PLA/PBS/WF composite degraded faster than PLA during three months in natural soil, which was due to the fast degradation rate of PBS. POLYM. COMPOS., 38:2841–2851, 2017. © 2016 Society of Plastics Engineers  相似文献   

13.
The aim of this work is to study the effect of kenaf volume content and fiber orientation on tensile and flexural properties of kenaf/Kevlar hybrid composites. Hybrid composites were prepared by laminating aramid fabric (Kevlar 29) with kenaf in three orientations (woven, 0o/90o cross ply uni‐directional (UD), and non‐woven mat) with different kenaf fiber loadings from 15 to 20% and total fiber loading (Kenaf and Kevlar) of 27–49%. The void content varies between 11.5–37.7% to laminate with UD and non‐woven mat, respectively. The void content in a woven kenaf structure is 16.2%. Tensile and flexural properties of kenaf/Kevlar hybrid composites were evaluated. Results indicate that UD kenaf fibers reinforced composites display better tensile and flexural properties as compared to woven and non‐woven mat reinforced hybrid composites. It is also noticed that increasing volume fraction of kenaf fiber in hybrid composites reduces tensile and flexural properties. Tensile fracture of hybrid composites was morphologically analysed by scanning electron microscopy (SEM). SEM micrographs of Kevlar composite failed in two major modes; fiber fracture by the typical splitting process along with, extensive longitudinal matrix and interfacial shear fracture. UD kenaf structure observed a good interlayer bonding and low matrix cracking/debonding. Damage in composite with woven kenaf shows weak kenaf‐matrix bonding. Composite with kenaf mat contains the high void in laminates and poor interfacial bonding. These results motivate us to further study the potential of using kenaf in woven and UD structure in hybrid composites to improve the ballistic application, for example, vehicle spall‐liner. POLYM. COMPOS., 36:1469–1476, 2015. © 2014 Society of Plastics Engineers  相似文献   

14.
Bio‐based, biodegradable in soil, as well as degradable polyethylene mulching films with pro‐oxidants, have been introduced in the market in an effort to deal with the serious problem of managing plastic waste streams generated from conventional mulching films. In a previous experimental investigation, a series of naturally degraded under water melon cultivation conditions linear low density polyethylene (LLDPE) mulching films with pro‐oxidants, buried in the field for 8.5 years, were recovered intact even though undergoing a continuous slow abiotic degradation in soil. The aim of the present article was to simulate the behavior of the LLDPE mulching films with pro‐oxidants under a much longer time‐scale (e.g. some decades). Toward this purpose, samples of LLDPE with pro‐oxidants film were artificially degraded to simulate severe degradation/fragmentation of these films while been buried in the soil for many years, following the end of the cultivation season. Further degradation of these severely degraded samples was investigated by burying them in the soil over a period of seven years. During this burial period, all degradation parameters and their evolution with time were measured. The artificially degraded LLDPE film samples with pro‐oxidants, in contrast to the naturally degraded film that remained intact for 8.5 years, were gradually transformed into tiny micro‐fragments in the soil. These fragments, through a continuing abiotic degradation process under natural soil conditions are eventually transformed into invisible micro‐fragments. The fate of these micro‐fragments and their long‐term impact to the environment and human health is unpredictable. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42289.  相似文献   

15.
In order to improve the degradability of polylactic acid (PLA) composites and screen PLA degradation microorganisms. Sodium alginate was added into the wheat straw/PLA composites, and both composites (with/without sodium alginate) were buried in natural soil for 100 consecutive days subsequently. Weight loss and characterization of the PLA composites, carbon and nitrogen content in soil and microbial community composition were detected after degradation, with the result that the degradability of the PLA composites was greatly improved after the addition of sodium alginate. The weight loss of PLA composites with sodium alginate was 8.5%, which was 1.81 times that of PLA composites without sodium alginate. Sodium alginate and/or wheat straw in the PLA composites took the lead in the beginning course of the degradation. The added sodium alginate serves the purpose of making it easier to degrade the crystallization zone of the PLA composites. Bionectriaceae in the soil shoots up in the number after degradation, signifying its potential to be part of the microorganism family serving to degrade PLA composites. The results would help reveal the degradation mechanism of PLA composites and provide support for the screening of PLA composites degradation microorganisms.  相似文献   

16.
Composites were fabricated with poly(lactic acid) and oil‐palm empty‐fruit‐bunch (EFB) fibers with extrusion; this was followed by an injection‐molding technique. Before compounding, the surface of the fiber was modified through ultrasound and poly(dimethyl siloxane) (PDMS). The influences of the ultrasound and PDMS on the water absorption and biodegradability of the composites were investigated. Additionally, the composites were buried under soil for 6 months, and their biodegradability was assessed through different characterization techniques, such as tensile testing and weight loss and diffussability measurement. The changes on the surface of the fibers due to treatment were examined by scanning electron microscopy analysis, and the influences on the biodegradability of the composites were observed. Functional group analysis and possible changes before and after degradation were also examined by a Fourier transform infrared spectrophotometric technique. The results analyses revealed that the treatment of fibers improved the density of the fibers and reduced the water uptake of the composites. The overall weight loss due to soil burial testing was found to be maximum for the untreated‐fiber‐based composites (6.8%), whereas the ultrasound‐ and silane‐treated composites showed the minimum value of weight loss (3.7%). The deterioration of the tensile strength due to degradation was found to be at a maximum for the untreated‐fiber‐based composite (27%), whereas the ultrasound‐ and silane‐treated‐fiber‐based composites showed a minimum value of 8%. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42784.  相似文献   

17.
Bis-isocyanoto polyester was synthesized by the polymerization of PPSe with MDI and reacted with 1,3-propanediol chain extender to obtain poly(ester urethane)s. The effect of chain extender and PPSe content in polyurethane was investigated. The polymers were characterized by 1H NMR, FT-IR, viscosity measurement, TGA and XRD. Their biodegradability was investigated by the hydrolytic degradation in NaOH solution (3% and 10%); enzymatic degradation by Rhizopus delemar lipase and soil burial degradation using garden-composted soil. Furthermore, the degraded film was characterized by molecular weight, intrinsic viscosity, DSC, XRD, FT-IR and surface morphology by SEM. The biodegradation study revealed that hydrolysis and soil burial degradation affected morphology of the PEUs. Hydrophobicity and hard segment seem to resist the hydrolytic and enzymatic degradability of PEU. Hydrolytic degradation was very rapid in 3% and 10% NaOH solutions at 37 °C, within 2 days 20% weight loss was observed. PEUs showed a much slower degradation rate under the R. delemar lipase at 37 °C. Experimental data showed that as soft segment increases biodegradation rate decreased. A significant rate of degradation was occurred in all PEU samples under soil burial condition. Surface morphology, which interconnected to good adhesion of bacteria on polymer surface, is considered to be a factor sensible for the biodegradation rate under soil burial condition.  相似文献   

18.
《国际聚合物材料杂志》2012,61(2-3):351-366
Abstract

Sago starch filled linear low density polyethylene (LLDPE) composites, have been prepared by melt mixing of the granular starch and LLDPE in a HAAKE internal mixer. The tensile, water absorption and enzymatic degradation properties of the composites have been determined. Incorporation of sago starch into LLDPE led to decrease in tensile strength and elongation at break of the composites. Up to 15 wt.% of sago starch could be added to LLDPE without adverse effects on the tensile properties. The water uptake increased with immersion time and the rate of absorption is strongly controlled by the immersion temperatures. Dramatic reduction in tensile properties were observed in the composites that were immersed in water at 90[ddot]C. The recovery of the tensile strength and elongation at break upon redrying is about 37.5 and 1.6% respectively. The permanent damage to the composites was attributed to severe hydrolysis of the starch particles. The enzymatic degradation study using oc-amylase revealed that both tensile strength and elongation at break reduced with time of treatment. Mode of failures of both LLDPE matrix and its sago starch filled composites, assessed by fracto-graphic analysis in a scanning electron microscope (SEM) are discussed.  相似文献   

19.
Sago starch was chemically modified through esterification using 2-dodecen-1-yl succinic anhydride (DSA) and propionic anhydride (PA) and three different solvents: [N,N dimethylformamide (DMF), triethylamine (TEA), and toluene (TOU)]. The effect of reaction times and temperatures on the modification was investigated. Evidence of anhydride modification was established by the weight percent gain (WPG) and was further confirmed by FTIR. The DSA–DMF and PA–DMF system, when subjected to the reaction condition of 120°C for 5 h, resulted in the highest WPG. Starch modified with 2-dodecen-1-yl succinic anhydride (MS) and propionic anhydride (MS2) was employed in preparation of composites. Samples of composites containing blends of MS/LLDPE and MS2/LLDPE with four different loadings of fillers (10, 25, 40 and 50% based on composite weight) were prepared. With unmodified ST/LLDPE, as the starch content increased, tensile modulus and water absorption increased—but tensile strength and elongation at break showed the opposite effect. With modification, the MS/LLDPE and MS2/LLDPE blends showed improved mechanical and water absorption properties as compared to ST/LLDPE.  相似文献   

20.
In this study, biodegradable poly(lactic acid) (PLA)/Kenaf core composites with different amount of Kenaf core were prepared using screw extrusion. The Structure, thermal stability, mechanical properties, and biodegradation of bio‐composites are evaluated. FTIR result shows the possible interaction between the Ken core and PLA matrix. The FESEM result showed that Kenaf core was uniformly disperse in PLA matrix. Tensile and flexural strength of PLA was improved Up to the 30%vol of kenaf core content. Young's modulus and hardness properties were improved by adding kenaf core into PLA matrix. Bio‐composite density has been decreased by adding more kenaf core and water absorption of the compound was increased linear. High Kenaf core content was also found to increase the rate of biodegradability of PLA/kenaf core. It can be proven by exposure of the samples to the environment and weight loss in soil burial analysis. POLYM. COMPOS., 35:1220–1227, 2014. © 2013 Society of Plastics Engineers  相似文献   

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