Starch-grafted-polypropylene/kenaf fibres composites. Part 2: thermal stability and dynamic-mechanical response

Materials & Design, 2010

This paper investigates the effects that processing parameters, including temperature and speed, have on the mechanical properties of kenaf fibre plastic composite. Kenaf fibre was used to fabricate a composite material along with polypropylene (PP) as a binding material. The composite was manufactured using a newly developed compression moulding machine. Tensile and impact tests were performed on the PP/kenaf composite to characterise its mechanical properties. The tensile properties of PP/kenaf composite increased by 10% after the addition of unidirectional kenaf fibre (UKF). However, its impact properties simultaneously deteriorated. Dynamic mechanical analysis (DMA) was carried out to examine the material properties. Results show that the storage modulus (E 0 ) and loss modulus (E 00 ) increase with the addition of UKF. However, its addition decreases the tan d amplitude. The fracture surface of PP/kenaf composite was investigated by SEM. The newly invented compression moulding machine illustrates a new trend in processing parameters of long kenaf fibre plastic composite.

Universiti Malaysia Terengganu Journal of Undergraduate Research

Renewable materials have some bearing on the environment and have since increased research works related to polymer composites. This work was conducted to investigate the effects of interwoven kenaf fibers and the use of kenaf fibers in composites. In this research, interwoven between kenaf and polyethylene terephthalate (PET) was prepared and epoxy was used as the polymer matrix to form composites. The kenaf fiber composites with various kenaf fiber contents (2, 5, 8, and 10 wt %) interwoven with (PET) fibers were prepared by using open mould method. The properties of kenaf/PET/epoxy composites (KPTE) were studied. The kenaf fiber composites characterization was determined based on their mechanical properties, water absorption, morphology and thermal properties. The tensile strength test was performed using Testometric machine. The finding shows that the strength increases as the amount of kenaf fibers in the composites increases. The composites with 10% kenaf fibers interwoven PET...

IOP Conference Series: Materials Science and Engineering

Composites of kenaf/unsaturated polyester containing 1layer up to 4 layers of kenaf fibre were studied to evaluate the mechanical and thermal properties. These composites were compared with a control system containing unsaturated polyester. The composite of different fibre layers was prepared using compression moulding techniques. The composites with x layers had the lowest tensile strength with slightly higher flexibility compared with those systems containing higher number of layers. The tensile properties of composites containing x layers demonstrated that the addition of fibre to the kenaf/unsaturated polyester composite was affected more than the incorporation of the. Thermogravimetric analysis of pure kenaf, unsaturated polyester and unsaturated polyester composite incorporated with 1, 2, 3 and 4 layers revealed significant differences in the decomposition temperature. Analysis by differential scanning calorimetry, equally, showed a decrease in thermal transitions with the 1 through 4layers. The results of the mechanical and thermal properties tests suggest that kenaf fibres improved the composite mechanical and thermal properties.

IOP Conference Series: Materials Science and Engineering, 2018

The effect polypropylene maleic anhydride (PPMAH) as a compatibilizer in mixing of polypropylene (PP) with kenaf fiber (KP) has been studied. Seven (7) different PP/KF composites ratio (100/0, 95/5, 90/10, 85/15, 80/20, 75/25 and 70/30) where compatibilizer use for PP/KF composite with fixed 3 wt% of maleic anhydride grafted polypropylene were carried out. In this project, all compound preparation was done by using a heated two-roll mill at a temperature of 180 °C for 7 minutes total of the mixing process. Then, the mixture was moulded by using a hot press machine at a temperature of 180 °C for a total 12 minutes to form 1 mm sheet and then cut into dumbbell shape. This sample was tested for mechanical properties include tensile strength, young modulus and elongation at break and morphology of the fracture surface of PP/KF composites. The result show PP/KF composite with compatibilizer has a higher tensile strength and young modulus compare to uncompatibilizer PP/KF composite. The adhesion between fiber and matrix has improved with addition of PPMAH compatibilizer. It make the PP/KF composite increase the stiffness and tensile strength. The scanning electron microscopy (SEM) study of tensile fracture surfaces of the PP/KF composites also indicates improved adhesion of kenaf fiber with polypropylene matrix with the presence of PPMAH compatibilizer.

The properties of short fibre composites are fibre dispersion, fibre length distribution, fibre orientation, and fibre-matrix adhesion as these affect the thermal and crystallinity of ABS/epoxy coated kenaf fibre composite. Short kenaf fibres of 3mm were coated with 40% epoxy resin after the fibres had been treated with 6% NaOH, dried and analysed thermally, compounded using curative range between 0 and 8%, moulded at 210 o C temperature and characterized using dual cantilever analyser and XRD diffractometer. The thermal analysis and crystalinity showed that 4% curative performed best while storage and loss moduli decreased and increased from 0 to 4% curative respectively. It can be inferred that maximum cured epoxy coated kenaf fibres at 4% can be stable thermally and well crystallized.

IOP Conference Series: Materials Science and Engineering, 2019

Kenaf is a non-woody plant, which has high potential fiber to be used as polymer matrix reinforcement. Different compositions of kenaf fiber as bio reinforcing material at different fabrication process parameters will produce different biocomposite properties. This study uses kenaf fibers in the composition of 10, 20, and 30 wt.% as reinforcing material. Kenaf fiber and epoxy resin were mixed based on predetermined compositions, stirred using a mechanical stirrer at 200 rpm for 10 minutes. Then the mixture is poured into a mold and placed on a hot press machine. Pressure of 50 kg/mm 2 for 30 minutes at 150 0 C is used to produce kenaf fiber/epoxy biocomposite. The result showed that the increasing of kenaf fiber content in the matrix is succeeded to increase the flexural and impact strength of the biocomposite kenaf fiber/epoxy produced. The highest flexural strength (136 MPa) and highest impact strength (180 KJ /m 2) were obtained at a composition of 30 wt.% Kenaf fiber.

Key Engineering Materials, 2011

In evaluating thermoplastics for their effective performance during processing, rheology properties are very useful. Similarly, in designing processing apparatus, knowledge of rheological behavior of composite melt is critical. In this study, melt flow and viscosity behavior of polypropylene/kenaf fibre composite was investigated using a single-screw extruder. Subsequently, flow behavior of the compounded formulation were evaluated by comparing the melt flow index, flow curve and viscosity curve of the PP and that of the composites at 190 o C processing temperature and varying the fibre size. There appears to be a positive linear increase of the apparent shear stress with increase in the apparent shear rate and, as expected, viscosity values for the composite samples are much higher than the PP especially at larger fibre size. The additional of kenaf fibre in composite reduces the MFI value basically because of the hindrances in the plastic flow of the polymer. In addition the increase in viscosity with increase in fibre loading might contributed to the high specific area of the fibre in the matrix thereby increasing the shear stress in the composite. Moreover loading of polymer system with fibre tends to disturb or disorganize the normal free movement of the polymer and certainly hindered the mobility chain segments in flow.

Journal of Polymers and the Environment, 2013

Non-woven composites were produced using kenaf (bast) fiber and polypropylene (PP) fiber. The effects of needle punching process, number of needle and kenaf fiber loadings on the properties of non-woven composite were studied. The aspect ratio of kenaf fiber was also measured in this study. The aspect ratio of most of kenaf fiber used was in the range of 200-400. The results indicated that the mechanical strength of the non-woven composite was significantly influenced by the percentage of kenaf fiber. This may due to the evenly mixed kenaf and PP fibers during carding process prior to the mechanical interlocking by needle punching process. The tensile strength, modulus and toughness were enhanced with the incorporation of carded and needle punched fibers. The number of needle used in needle punching process had a significant effect on the strength of the composite. This was evident in SEM micrograph where composite prepared from carded to needle punched non-woven web showed better wettability as compared to composite prepared from carded non-woven web only. However, no significant difference was observed in water absorption and thickness swelling tests for composites prepared with different number of needles.

2015

This work is aimed at incorporating natural bast fibre, kenaf into engineering thermoplastic ABS at its high melting temperature of 230C, without degradation of the fibre. The idea was carried out by pre-coating the fibre with 40% thermoset which was later cured at high temperature in Haake internal mixer where compounding took place with ABS. Poly (acrylonitrile-butadiene-styrene) (ABS) is a known popular engineering thermoplastic for its unique properties which include its excellent mechanical response, good processing characteristics, chemical resistance and fine surface appearance. ABS composites reinforced with modified kenaf fibres have resulted into increased tensile properties up to the optimum level of the curative loading as it improved the thermal stabilities of the fibres in the composites. The moulding temperatures have also affected the tensile properties significantly.

Industrial & …, 1995

Kenaf (Hibiscus cannabinus) is a fast growing annual growth plant that is harvested for its bast fibers. These fibers have excellent specific properties and have potential to be outstanding reinforcing fillers in plastics. In our experiments, the fibers and polypropylene (PP) were blended in a thermokinetic mixer and then injection molded, with the fiber weight fractions varying to 60%. A maleated polypropylene was used to improve the interaction and adhesion between the nonpolar matrix and the polar lignocellulosic fibers. The specific tensile and flexural moduli of a 50% by weight (39% by volume) of kenaf-PP composite compare favorably with a 40% by weight of glass fiber-PP injection-molded composite. These results suggest that kenaf fibers are a viable alternative to inorganic/mineral-based reinforcing fibers as long as the right processing conditions are used and they are used in applications where the higher water absorption is not critical.