Showing papers by "Azman Hassan published in 2015"

Rice Husk Filled Polymer Composites

Abstract: Natural fibers from agricultural wastes are finding their importance in the polymer industry due to the many advantages such as their light weight, low cost and being environmentally friendly. Rice husk (RH) is a natural sheath that forms around rice grains during their growth. As a type of natural fiber obtained from agroindustrial waste, RH can be used as filler in composites materials in various polymer matrices. This review paper is aimed at highlighting previous works of RH filled polymer composites to provide information for applications and further research in this area. Based on the information gathered, application of RH filled composites as alternative materials in building and construction is highly plausible with both light weight and low cost being their main driving forces. However, further investigations on physical and chemical treatment to further improve the interfacial adhesion with polymeric matrix are needed as fiber-polymer interaction is crucial in determining the final composite properties. Better understanding on how the used polymer blends as the matrix and secondary fillers may affect the properties would provide interesting areas to be explored.

A review of recent developments in flammability of polymer nanocomposites

Abstract: Polymer nanocomposite flame retardancy has become a critical parameter in industrial material application. Recent environmental policies have prohibited the incorporation of halogenated flame-retardant compounds into polymers owing to the high level of environmental degradation caused by high levels of toxic gas and smoke emission. The demand for zero-halogen flame-retardant compounds by both researchers and manufacturers is due to the inherent advantages accruable from their incorporation like very minimal toxic emission, minimal smoke release, zero corrosive gas release, reduced corrosion activities and absence of dripping in fire condition. This has necessitated the quest for eco-compliant replacements for halogenated flame suppressants. Recent insight has shown the eco-compliancy of exfoliated graphene nanoplatelets as flame retardants when incorporated into polymer nanocomposites (PNCs). Relative to the propensity to retard flame, increasing quantities of exfoliated graphene nanoplatelets have exhibited the capability to significantly repress critical flammability parameters like heat release rate (HRR), peak HRR (PHRR), rate of carbon monoxide production, smoke production rate and total mass loss rate while simultaneously increasing limiting oxygen index, time of ignition and total PHRR, thereby retarding flammability and creating better chance to reduce loss and casualty in real-life fire situation through the formation of even layers of carbonaceous char in the condensed phase capable of efficiently suppressing the thermal decomposition caused by oxygen and heat to the polymer matrix and cutting off the flaming path. This paper gives an insight into recent developments in flame retardancy of PNCs, with special emphasis on the flame-retardancy propensity of exfoliated graphite nanoplatelets.

Enhanced ductility and tensile properties of hybrid montmorillonite/cellulose nanowhiskers reinforced polylactic acid nanocomposites

Abstract: Montmorillonite (MMT)/cellulose nanowhiskers (CNW) reinforced polylactic acid (PLA) hybrid nanocomposites were prepared by solution casting. CNW were isolated from microcrystalline cellulose using a chemical swelling method. An initial study showed that the optimum MMT content, for mechanical properties, in a PLA/MMT nanocomposite is five parts per hundred parts of polymer (phr). Various amounts of CNW were added to the optimum formulation of PLA/MMT to produce PLA/MMT/CNW hybrid nanocomposites. FT-IR analysis indicated the formation of some polar interactions, resulting in enhanced tensile properties of the hybrid nanocomposites. The highest tensile strength for the hybrid nanocomposites was obtained for a 1 phr CNW content. Young’s modulus was also found to increase with an increasing CNW content. Interestingly, the strain to failure (or ductility) of the hybrid nanocomposites increased significantly from ~10 to ~90 % with the addition of 1 phr CNW. This increase in ductility was proposed to be due to the nucleation of crazes and the formation of shear bands in the PLA.

Mechanical and thermal properties of SEBS-g-MA compatibilized halloysite nanotubes reinforced polyethylene terephthalate/polycarbonate/nanocomposites

Abstract: In this study, the effect of maleic anhydride grafted styrene-ethylene-butylene-styrene (SEBS-g-MA) content on mechani- cal, thermal, and morphological properties of polyethylene terephthalate/polycarbonate/halloysite nanotubes (PET/PC/HNTs) nano- composites has been investigated. Nanocomposites of PET/PC (70:30) with 2 phr of HNTs were compounded using the counter rotating twin screw extruder. A series of formulations were prepared by adding 5-20 phr SEBS-g-MA to the composites. Incorpora- tion of 5 phr SEBS-g-MA into the nanocomposites resulted in the highest tensile and flexural strength. Maximum improvement in the impact strength which is 245% was achieved at 10 phr SEBS-g-MA content. The elongation at break increased proportionately with the SEBS-g-MA content. However, the tensile and flexural moduli decreased with increasing SEBS-g-MA content. Scanning elec- tron microscopy revealed a transition from a brittle fracture to ductile fracture morphology with increasing amount of SEBS-g-MA. Transmission electron microscopy showed that the addition of SEBS-g-MA into the nanocomposites promoted a better dispersion of HNTs in the matrix. A single glass transition temperature was observed from the differential scanning calorimetry test for compatibi- lized nanocomposites. Thermogravimetric analysis of PET/PC/HNTs nanocomposites showed high thermal stability at 15 phr SEBS-g- MA content. However, on further addition of SEBS-g-MA up to 20 phr, thermal stability of the nanocomposites decreased due to the excess amount of SEBS-g-MA. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42608.

Polylactic acid/polycaprolactone nanocomposite: influence of montmorillonite and impact modifier on mechanical, thermal, and morphological properties

Abstract: This article investigates the performance of polylactic acid (PLA)/polycaprolactone (PCL)/montmorillonite (MMT) nanocomposites toughened with metallocene-catalyzed linear low-density polyethylene (mLLDPE), in terms of mechanical, thermal, and morphological properties. All the results were compared and the influence of MMT and mLLDPE on the final properties was observed and reported. mLLDPE decreased the modulus and the strength of PLA/PCL and its nanocomposites due to its inherent lower rigidity compared to PLA/PCL nanocomposites. Moreover, incorporation of clay significantly increased mechanical and thermal stability of the nanocomposites. Scanning electron microscopic images confirmed that MMT acted as a compatibilizer, whereas it reduced the size of the droplets. It has been suggested that improvements in properties are related to good dispersion of clays within the matrix. However, further addition of MMT beyond 2 parts per hundred (phr) level decreases all the properties of PLA/PCL/mLLDPE/MMT nanocom...

Mechanical, thermal and chemical resistance of epoxidized natural rubber toughened polylactic acid blends

Abstract: Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical resistance and water absorption properties of the blends were studied using standard methods. The toughness of the blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in crystallization temperature (Tc) as ENR content increases while the glass transition temperature (Tg) remained unchanged. Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the chemical resistance of the blends.

Use of epoxidized natural rubber as a toughening agent in plastics

Abstract: At present, the rubber toughening of plastics has become an attractive field of study in polymer science and technology because brittleness is known to be a drawback in many engineering plastics; it can cause premature failure during application. Among existing rubber materials, epoxidized natural rubber (ENR) has been widely used as an impact modifier or toughening agent in a large number of engineering plastics; in particular, it enhances the impact strength, which deteriorates with the incorporation of other additives, such as fillers and flame retardants. ENR is a modification product from natural rubber produced via an epoxidation reaction. ENR also has good chemical resistance. In this review, we aim to provide a concise current status in the field of ENR toughening agents for plastics with a brief discussion of their associated problems and potential applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42270.

Properties of ethylene–vinyl acetate filled with metal hydroxide

Abstract: In this study, the properties of ethylene–vinyl acetate (EVA) and EVA filled with aluminum (aluminum trihydrate; ATH) and magnesium hydroxide (MH) as halogen-free flame-retardant materials were studied. Scanning electron microscopic analysis revealed that MH in EVA matrix is platy in structure, considerably broad size distribution and well homogeneously distributed, whereas ATH particles are smaller and much more homogeneous in size. Addition of ATH or MH to EVA had an impressive affection on the thermal aging and flame tests but impaired the blend mechanical properties. This research explored that in comparison with ATH, addition of MH to EVA blends was more efficient and suitable in all mechanical, thermal, and flammability tests.

Effect of microcrystalline cellulose on biodegradability, tensile and morphological properties of montmorillonite reinforced polylactic acid nanocomposites

Abstract: The objective of this study is to investigate the effects of incorporating microcrystalline cellulose (MCC) on montmorillonite (MMT) reinforced polylactic acid (PLA) nanocomposites prepared by solution casting method. The biodegradability, tensile and morphological properties of PLA hybrid composites were investigated using soil burial test, tensile testing machine, field emission scanning electron microscopy, transmission electron microscopy (TEM) and optical microscopy. In addition, Fourier transform infrared spectroscopy (FTIR) was used to observe the interactions between fillers and PLA in the hybrid composites. Various amounts of MCC were added to the optimum formulation which was 5 phr of MMT to produce PLA/MMT/MCC hybrid composites. The biodegradability of hybrid composites increased compared to nanocomposite with 5 phr MMT content and neat PLA. Interestingly, the ductility of PLA/MMT/MCC hybrid composites increased significantly with the addition of 1 phr MCC filler. FTIR analysis revealed some interactions between PLA and both fillers in the hybrid composites. X-ray diffraction and TEM analyses revealed that incorporation of MCC filler into optimum formulation of PLA/MMT nanocomposites slightly decreased the interlayer spacing of MMT in the PLA/MMT/ MCC hybrid composites.

Effects of ENR and OMMT on barrier and tensile properties of LDPE nanocomposite film

Abstract: The effects of organo-modified montmorillonite (OMMT) nanoclay and epoxidized natural rubber (ENR) content on the gas barrier, tensile, and the thermal properties of nanocomposite films based on low-density polyethylene (LDPE) are investigated Linear low-density polyethylene-grafted maleic anhydride (LLDPE-g-MA) is used as a compatibilizer to obtain better dispersion of the nanoclay in the blends The blends, with various amounts of ENR (0–10) wt%, are melt-compounded and extruded using a blown film extrusion single screw The tensile properties of films are studied in machine direction (MD) The gas permeability of films is studied via constant pressure and a soap bubble flow meter The melting and crystallization behaviors of films are examined via differential scanning calorimetry (DSC) Chemical interactions of composite blends are examined via Fourier transform infrared (FTIR) spectroscopy An addition of 6 wt% nanoclay improved the tensile modulus by about 11 % It further reduced the oxygen permeability by about 83 % Although introducing OMMT decreased the percentage of crystallinity (XC), the presence of LLDPE-g-MA in the nanocomposite enhanced the property due to better intercalation between the phases Incorporation of ENR caused an increase in the Young’s modulus for compatibilized nanocomposite systems, attributed to an interaction among clay, compatibilizer, and ENR, and cross-linking effects of ENR molecules However, ENR decreased the permeability of the film due to the ability of amorphous regions to form crystallized structures during the blown process, and cross-linking effects of ENR In addition, ENR reduced the XC of nanocomposites due to an interference that exists in the form of ENR molecular incorporation The FTIR spectra showed that the maleic anhydride group in LLDPE-g-MA reacted in situ with the epoxy groups of ENR, which was an evidence of grafting reaction

Mechanical and thermal properties of rubber toughened poly(lactic acid)

Abstract: The effect of rubber toughening on mechanical and thermal properties of poly (lactic acid) (PLA) was investigated by using three types of rubbers; natural rubber (NR), epoxidized natural rubber (ENR) and core-shell rubber (CSR). The PLA/rubber blends were prepared by melt blending in a counter-rotating twin-screw extruder, where the rubber content for all blends was kept at 5 wt%. It was found that the addition of the rubbers increased the impact strength for all blends as compared to pure PLA. On the other hand, all PLA/rubber blends showed notable decrease of Young’s modulus especially for PLA/NR blend which decreased by 72% than pure PLA. Similarly, significant decrease of tensile strength was also observed for all PLA/rubber blends. PLA/ENR blend showed a morebalance mechanical properties with fairly significant improvement of impact strength and moderate decrease of tensile strength, Young’s modulus and elongation at break. In general, PLA/NR blend showed the highest overall impact strength, while the PLA/CSR showed the highest tensile strength and Young’s modulus among the blends. Thermal analysis revealed that the Tg of PLA decreased with incorporation of the three types of rubbers with NR showing the largest decrease. This study indicates that NR, ENR and CSR are effective in enhancing toughness of PLA

Effect of zinc borate on mechanical and dielectric properties of metallocene linear low-density polyethylene/rubbers/magnesium oxide composite for wire and cable applications

Abstract: The effect of zinc borate (ZB) quantity on the mechanical and dielectric properties of 20 phr magnesium oxide/10 % rubbers (9/1 NR/ENR-50)/metallocene linear low-density polyethylene (mLLDPE) in the presence of N,N-m-phenylene bismaleimide (HVA-2) compatibilizer was investigated for wire and cable applications. With the increase in ZB loading, the tensile strength and the elongation-at-break of the composites decreased while the tensile modulus increased. In all composites, the strain-induced crystallization phenomenon at 200 % elongation was being observed in the stress–strain curves. Moreover, the dielectric strength, dielectric loss, permittivity and volume resistivity at frequency of 50 Hz were investigated. The permittivity of all composites increased with a rise in the voltage within the range of 1–5 kV. The loading of ZB in the composites improved the permittivity and volume resistivity as compared to the neat mLLDPE. The dielectric loss increased and 2 phr ZB composite displayed the highest dielectric loss among all other composites. On the other hand, the breakdown decreased with increasing ZB loading and the highest breakdown was observed in the 6 phr ZB composite. It was concluded that all composites are suitable for wire and cable application and the best result based on dielectric properties was observed in the 6 phr ZB composite.

Comparative Economic Investigation Options for Liquefied Petroleum Gas Production from Natural Gas Liquids

Abstract: There is new trend in the value of oil and gas in the world, with the value of Liquefied Petroleum Gas (LPG) soaring higher. It is due to its uses as a potential fuel in the several parts of the world, its demand in the petrochemical industries for plastics and automotive composites productions, and other uses. These results in steadily increases in price. There is also increase in volume of feed gas, which demands efficient LPG processing and recovery technology. This paper mainly focuses on comparative economic investigation options for Liquefied Petroleum Gas plant, which processes feed from natural gas wells and dehydrating units to produce Liquefied Petroleum Gas along with natural gasoline having a higher value as separate product. Recovery of LPG is possible but raises both the initial cost of plant and operational cost considerably. The value of LPG recovered should be high enough to widen the operating margins between the processing costs and the market price for which the recovered liquids can be sold. Therefore, the most economic means of extracting this product must be used. This was done using two alternatives; the Conventional Fractionation process and Single column overhead recycle process (SCORE). Both alternatives were simulated with Hysys and are analyzed based on product recovery level, energy required and fixed capital cost. There are two feeds to the plant, one from the natural gas wells and the other from dehydrating units of natural gas processing plants with a total flow rate of 6.99 MMSCFD. Analysis of result from modeling shows that Single column overhead recycle process has a total product recovery of 97.2 % while Conventional fractionation process has a total recovery of 88.5 %, the require energy margin between the alternatives is about 38.9 % in favor of conventional process and the fixed capital cost is in the favor of Single column process. Sensitive to choosing the most economic option of LPG recovery between the conventional process and SCORE process is the recovery level of LPG from each of the options, total energy required and the cost of the equipment. From the analysis, it shows that, it is more economical to use the Single column overhead recycle process, as compared to conventional fractionation process.

Tensile, oxygen barrier and biodegradation properties of rice husk-reinforced polyethylene blown films

Abstract: The past few years have witnessed a renewed interest in developing new ecofriendly materials, sparked mostly by the nonbiodegradability of most of the polymeric materials. In this context, incorporation of biofibres as load-bearing constituents in polymeric composites is a highly attractive research line for the development of ecofriendly composites. An experimental study, with the overall aim of making environmentally compatible packaging film, was conducted to investigate the influence of rice husk (RH) loading on morphological, tensile, oxygen barrier and biodegradation properties of low-density polyethylene (LDPE)-based extrusion blown films. Various compositions were prepared with varying contents of RH and the properties were correlated with the loading of RH. Morphological observations revealed that there were micro-voids at interface and the RH particles start agglomerating beyond 5 wt%. The tensile, tear and oxygen barrier properties decreased as the loading of RH increased. Soil burial tests revealed that the composite films are biodegradable and RH loading has significant impact on rate of biodegradation.

Thermal Properties and Mechanical Performance of Unsaturated Polyester/Phenolic Blends Reinforced by Kenaf Fiber

Abstract: In this study, unsaturated polyester resin (UP) is blended with resole type phenolic resin (PF) to develop a material with good flame retardancy. The UP/PF resin blends are expected to show good compatibility when compounded with natural fibers which in this research is kenaf fiber. The thermal properties were investigated by thermogravimetric analysis (TGA). The char yields of the UP/PF blends reinforced kenaf composite increased with PF content. The degradation temperature of the composite at 50% weight loss rose to 410.13°C as the PF content was increased to 40%. The result shows with additional of PF to UP resin enhance the thermal stability of the composite. Meanwhile the mechanical performance of UP/PF kenaf composite were evaluated and compared with neat UP and PF reinforced with kenaf fiber using tensile and impact testing. The mechanical properties of all resin blends at different mixing proportions slightly decrease by increasing the phenolic content but shown an improvement as compared to the PF kenaf fiber composite. The fracture surface morphology of the tensile testing samples of the composites was performed by scanning electron microscopy (SEM).

Effect of Compatibilizer Content on the Mechanical and Morphological Properties of PET/PP (70/30) Blends

Abstract: This work investigates the effect of compatibilizer concentration on the mechanical properties of compatibilized polyethylene terephthalate (PET) /polypropylene (PP) blends. A blend containing 70 % (wt) PET, 30 % (wt) PP and 5 - 15 phr compatibilizers were compounded using counter rotating twin screw extruder and fabricated into standard test samples using injection molding. The compatibilizer used is styrene-ethylene-butylene-styrene grafted maleic anhydride triblock copolymer (SEBS-g-MAH). Morphological studies show that the particle size of the dispersed PP phase is dependent on the compatibilizer content up to 10 phr. Impact strength and elongation at break showed maximum values with the addition of 10 phr SEBS-g-MAH and a corresponding decrease in flexural and young’s moduli; and strengths.. Overall the mechanical properties of PET/PP blends depend on the control of the morphology of the blend and can be achieved by effective compatibilization using 10 phr SEBS-g-MAH.

Comparing the effects of microcrystalline cellulose and cellulose nanowhiskers extracted from oil palm empty fruit bunch on mechanical and thermal properties of polylactic acid composites

Abstract: This chapter discusses polylactic acid (PLA) reinforced with microcrystalline cellulose (MCC) and cellulose nanowhiskers (CNW) extracted from oil palm empty fruit bunches. The addition of MCC and CNW into PLA increases the thermal stability of PLA. The Young's modulus of PLA improved by 17% and 36% at 5 per h MCC and CNW loading, whereas the elongation at break decreases to 51% and 70%, respectively. Interestingly, incorporating of 3 per h CNWs into PLA matrices significantly increases the tensile strength by 84% as opposed to that of PLA (16.6 MPa), whereas the similar loading of MCC contrarily decreases their tensile strength by 17%.

Effect of Chitosan-Grafted-Poly (Methyl Methacrylate) Content on Mechanical Properties and Thermal Degradation of Poly (Vinyl Chloride) Composites

Abstract: The graft copolymerization was carried out under nitrogen atmosphere using the free radical initiation technique. The blend formulations were first dry blended using a mixer before being milled into sheets on a two-roll mill at 170°C, and then hot pressed into composites specimens at 175°C for 10 min. The objective of this study to investigate the mechanical and thermal properties of PVC blends. The flexural strength and modulus of ungrafted composites increased with increasing filler content from 2 to 10 part per hundred resin (phr) while the grafted composites also increased only from 2 to 6 phr filler content. The flexural modulus of ungrafted was higher compared to the grafted composites whereas the grafted showed good flexural strength than ungrafted composites. The impact strength of both composites decreased with increasing filler content but the ungrafted composites showed good toughness than grafted composites. The thermal stability of both composites increased compared to unfilled PVC.

Effect of Natural Rubber/Epoxidized Natural Rubber (90/10) on Dielectric Properties and Crystallization of Metallocene Linear Low Density Polyethylene

Abstract: The effects of different amounts of natural rubber/epoxidized natural rubber (90/10 NR/ENR-50) blended with metallocene linear low density polyethylene (mLLDPE) with HVA-2 compatibilizer on the permittivity, dielectric loss, breakdown and volume resistivity at frequency of 50 Hz were investigated. Increasing the voltage with a range 1-5 kV increased the permittivity of both virgin mLLDPE and its blends. The permittivity, dielectric loss and breakdown of mLLDPE continuously decreased with increasing rubber content, but the AC volume resistivity of mLLDPE continuously increased with the rubber content. The degree of crystallinity of the mLLDPE composites was determined by differential scanning calorimetry. The lowest crystallinity and the maximum density of physical cross-links were observed in 10% rubber/mLLDPE blend. Increasing the proportion of rubber decreased the melting points of the blends. The FTIR showed that the epoxy groups and double bonds were absent from all the blends while the carbonyl group appeared in all cases.

Effect of weathering on the properties of recycled high density polyethylene based nonmetallic printed circuit boards waste composite

Abstract: The weathering performances of nonmetallic printed circuit boards (PCB)-filled recycled high-density polyethylene (rHDPE) was investigated in this study. The compression molded rHDPE/PCB composite was exposed to both natural and accelerated weathering attacks. The durability of rHDPE/PCB composites was compared to neat unfilled rHDPE and virgin HDPE (vHDPE). When the exposure time increased, the color of rHDPE faded faster than vHDPE. The surface of composites with 30 and 50 wt% nonmetallic PCB flaked off after being exposed to both weathering conditions. Prolonged weathering exposure also caused loss of impact strength of all the samples with and without nonmetallic PCB filler. In general, composites with 30 and 50 wt% nonmetallic PCB is more resistible to weathering attacks as compared to unfilled rHDPE.

Effects of Halloysite Nanotubes on Mechanical and Thermal Stability of Poly(Ethylene Terephthalate)/Polycarbonate Nanocomposites

Abstract: The objective of this study is to investigate the effect of halloysite nanotubes (HNTs) loading on mechanical and thermal properties of poly(ethylene terephthalate)/polycarbonate (PET/PC) nanocomposites. Nanocomposites containing 70PET/30PC and 2-8 phr HNTs were prepared by twin screw extruder followed by injection moulding. As the percentage of HNTs increased, the flexural modulus increased. However, the flexural strength decreased with increasing HNTs content. The impact strength also decreased when HNTs increased. Thermogravimetry analysis of PET/PC/HNTs nanocomposites showed higher thermal stability at high HNTs content. However, on further addition of HNTs up to 8 phr, thermal stability of the nanocomposites decreased due to the poor dispersion of HNTs.

Cellulose Nanowhiskers Reinforced Green Nanocomposites: Some Recent Development

Abstract: Cellulose is the most abundant biomass material in nature. Due to their abundance, high strength and stiffness, low weight and biodegradability, cellulose materials serve as promising candidates for bio-composites production. Extracted from natural fibres, its hierarchical and multi-level organization allows different kinds of cellulosic fillers to be obtained; microcrystalline cellulose (MCC) and cellulose nanowhiskers (CNW). Because of the high aspect ratio and nanoscopic size, CNW has shown to be an effective reinforcement to many polymers. The use of CNW as reinforcements in nanocomposites is becoming increasingly attractive leading to green nanocomposites; biodegradable and renewable. Among the green polymers, polylactic acid (PLA) acid has shown to be very popular due to the good mechanical properties. This paper will provide a review of recent studies on the use of CNW in various green polymers with greater emphasis on PLA. Comparison between the effects MCC and CNW in the nanocomposites will also be discussed.

Effect of acid hydrolysis time on tensile and morphological properties of microcrystalline chitin filled polylactic acid biocomposites

Abstract: The objective of this study is to investigate the effect of acid hydrolysis time on microcrystalline chitin (MCC) filled polylactic acid (PLA) biocomposites using solution casting method. MCC was produced from commercial chitin using controlled hydrolysis process at four different hydrolysis time; 15, 30, 45 and 60 min. The tensile and morphological properties of PLA/MCC biocomposites were investigated using tensile testing machine and atomic force microscopy (AFM), respectively. Tensile strength and Young’s modulus of PLA/MCC biocomposites increased gradually by increasing hydrolysis time. The biocomposites with longest hydrolysis time (60 min) showed the higher tensile strength, Young’s modulus and elongation at break values. AFM analysis showed homogeneous dispersion of MCC fillers with smaller particles size at longer hydrolysis time, resulted in smother surface morphology compared to biocomposites with shorter hydrolysis time.

Full Factorial Design Analysis on Mechanical Properties of Electron Beam Irradiated-Flame Retarded LDPE/EVA Composites

Abstract: This study aims to investigate the effect of three factors, namely alumina trihydrate (ATH), montmorillonite (MMT) and irradiation dosage on the mechanical properties (tensile strength and elongation at break) of flame-retarded LDPE-EVA composites. In this study, full factorial design analysis was used to examine the effects of factors and their combination interactions on mechanical properties. ATH is the most significant factor in affecting the tensile strength of LDPE-EVA blends due to the poor compatibility effect between ATH particles and LDPE-EVA matrix. However, MMT is the least significant factor on tensile strength of LDPE-EVA composites. ATH was the most significant in affecting the elongation at break of LDPE-EVA blends. This is because the increasing of ATH amount in LDPE-EVA matrix could restrict the mobolity of polymer chains in LDPE-EVA matrix. However, the factor of irradiation dosage was found to be insignificant in affecting the elongation at break of LDPE-EVA blends.

Mechanical, Thermal and Chemical Resistance of Epoxidized Natural Rubber Toughened Polylactic Acid Blends (Rintangan Mekanikal, Termal dan Kimia Adunan Asid Polilaktik Diperkukuhkan dengan Getah Asli Terepoksida)

Abstract: Polylactic acid (PLA)/Epoxidized natural rubber (ENR-50) blends were prepared by melt extrusion followed by injection molding to fabricate the test samples. The effect of ENR-50 loadings on the morphological, mechanical, chemical resistance and water absorption properties of the blends were studied using standard methods. The toughness of the blend improved with ENR loading up to 20 wt. % but flexural and tensile strength decreased. The balanced mechanical properties were obtained at 20 wt. % ENR-50 loading. SEM showed good distribution and increased ENR particle size as ENR content increased from 10 to 30 wt. %. The differential scanning calorimeter (DSC) showed a steady drop in crystallization temperature (T c ) as ENR content increases while the glass transition temperature (T g ) remained unchanged. Water absorption was observed to increase with ENR loadings. Increase in ENR content was also observed to reduce the chemical resistance of the blends.