Optical Properties of Cellulose Esters and Applications to Optical Functional Films

Cellulose esters are also employed for optical displays such as a liquid crystal display. In this application, various types of polymer films are required to construct a display, such as antiglare film, retardation film, protective film, brightness enhancement film and diffusion film. In particular, polarisation is an extremely important property for retardation and protective films. This property is expressed by birefringence Δn. In the case of oriented polymer films, the birefringence can be controlled by varying the stretching ratio. Consequently, it is always used for a retardation film that gives a specific retardation (Γ = d Δn; d is the film thickness). Another important optical film used in displays is the protective film, which is used to protect a polariser from moisture. Therefore, it has to be free from birefringence so that the polarised light will not be disturbed

Mechanical Properties of Kenaf Reinforced Polypropylene Composites Added with Oil Palm Shell Powder and Its Activated Carbon

The application of natural fibers in composite is very encouraging because of its many benefits such as more environmental friendly and cost reduction. The mechanical properties of kenaf fiber reinforced polypropylene composite added with two different types of bio-based fillers, namely oil palm shell powder (OPSP) and activated carbon of oil palm shell powder (ACOPSP) are studied. The composites were prepared by melt mixing of the materials using internal mixer, followed by extrusion and compression molding processes. The samples were prepared at 4 different weight percentage of filler content, i.e., 0, 5, 10 and 15 phc

Mechanical Properties of Plasticized Cellulose Ester Films at Room and High Temperatures

Cellulose ester is a biomass-derived material and exhibits excellent heat resistance and high transparency, properties required for optical film application. Recently, attention has been paid to cellulose esters due to their potential application as a functional film. Some cellulose esters such as cellulose acetate propionate (CAP) show extraordinary dispersion of orientation birefringence, in which the birefringence increases with increasing wavelength, a property required as a retardation film. The similar behaviour is also observed for cellulose triacetate (CTA) plasticized with tricresyl phosphate (TCP). In this study, the mechanical properties of pure and plasticized CAP and CTA at room and high temperatures are investigated to relate with their birefringence property. At room temperature, CTA film shows a higher brittleness than CAP film. At 15 K above their respective Tg, pure CAP and CTA can be stretched to draw ratio of 5.0 and 2.0, respectively. However, the addition of TCP slightly decreases the stretchability in both CAP and CTA to draw ratio of 4.5 and 1.5, respectively. The stretchability of both pure and plasticized CAP and CTA is found to increase with the increase of stretching temperature, which is useful to increase the value of orientation birefringence as it increases with draw ratio. However, birefringence value becomes lower at higher temperature. Thus, to obtain an optimum value of orientation birefringence, a balance between the draw ratio and stretching temperature has to be considered

Mechanical Properties and Failure Analysis of Laminated Glass Reinforced Composite with Various Gelcoat Thickness

The aim of this study is to evaluate the mechanical properties and study the failure of laminated glass reinforced composite coated with gelcoat of different thickness. Firstly, the gelcoat was applied to the mould using brush and subsequently, glass fiber reinforced composite laminates were fabricated on it using vacuum bagging technique. The mechanical properties of the composites various were tested by using tensile and three-point flexural tests. The fracture behaviour of different gelcoat thickness was observed using scanning electron microscope (SEM) to determine the failure behaviour that occurred. The flexural test was performed in two ways, i.e., gelcoat layer facing top and facing down. For both flexural tests, composite coated with 0.30 mm thick of gelcoat shows the highest mechanical strength. Tensile test is useful to investigate the interfacial bonding in between gelcoat and laminate composite. The composite coated with 0.40 mm of gelcoat showed the highest tensile strength, an increase of 38 % compared to the uncoated composite. It was observed that an increase in gelcoat thickness increased the brittleness of the laminated composite. From the failure analysis, failures were caused by the delamination of matrix between the plies, while the gelcoat was still strongly bonded with composite laminate

Effects of Filler Hybridization on the Mechanical Properties of NR/SBR/EPDM Rubber Blends

Hybridization of active fillers is one of the techniques utilized to enhance rubber properties. This study highlights the effects of filler hybridization on the mechanical properties of an industrial applied natural rubber/styrene butadiene rubber/ethylene propylene diene terpolymer (NR/SBR/EPDM) Rubber Mat compound reinforced by non-black fillers. Initially, three different rubber compounds were prepared; i) calcium carbonate (CaCO3)-filled NR [CaCO3NR] as reference sample, ii) precipitated silica (PSi)-filled NR/SBR/EPDM [PSiBR], and iii) calcined clay (ClCy)-filled NR/SBR/EPDM [ClCyBR]. From these compounds, composites of NR/SBR/EPDM were prepared. The ratio of PSi:ClCy was varied to study the effects of filler hybridization. CaCO3 was added for cost advantage industrially and its level was fixed. It was found that inclusions of ClCy and PSi individually and their hybridizations show higher tensile and tear strengths than the reference sample. Particularly, the largest improvement was found with the amount of ClCy which is higher than PSi. A ratio of PSi:ClCy in this particular range (1:2 to 2:3), seems to provide the optimum packing factor for good interaction between the fillers. SEM analysis suggests that better dispersion and packing of fillers due to size and shape of hybrid fillers play an important role in improving the composite properties

Mechanical Properties of Short Fiber and Non-Woven Kenaf Reinforced Polypropylene Composites: Effects of Oil Palm Shell Powder Addition

Kenaf is renowned for its renewable and environmental friendly properties. Recently, there is an interest on the application of kenaf-based material for high-end uses such as in the automotive industry. In this study, the effects of oil palm shell powder (OPSP) addition on the mechanical properties of kenaf reinforced polypropylene (PP) composites are investigated. Two types of kenaf are used in this study, i.e., non-woven and short fiber. For the former, the composites are fabricated by hot pressing a non-woven kenaf sheet sandwiched by thin PP sheets which have been mixed beforehand with OPSP by using internal mixer. For the latter, kenaf short fibers are mixed with OPSP using internal mixer, then compression molded by using hot press. In general, addition of OPSP was effective to improve the mechanical properties of non-woven kenaf reinforced PP composites, while the kenaf short fiber reinforced PP showed varied results. Composites reinforced with non-woven kenaf showed a larger increase in tensile strength, elongation at break and impact strength with the OPSP addition than those reinforced by kenaf short fibers

A Sustainable Polymer Composite from Recycled Polypropylene Filled with Shrimp Shell Waste

This research explores the potential of using recycled polypropylene (PP) incorporated with shrimp shell waste to produce a sustainable polymer composite. In this study, the mechanical and physical properties of recycled polypropylene/shrimp shell (rPP/SS) composites prepared by melt compounding and compression molding techniques were evaluated. The effects of SS loading were investigated by using various compositions of rPP/SS composites, ranging from 0 to 8 wt% SS that consists of two different sizes, i.e., fine and coarse SS. The composites were tested for their mechanical and physical properties using impact, tensile and water absorption tests. Furthermore, the morphology of the composites was examined by using a Scanning Electron Microscopy (SEM). Incorporation of SS was found to increase the Young’s modulus of the rPP, but the impact and tensile strength showed a decrease. However, we observed that both the impact and tensile strength improve with the further increase of the SS content. In other words, composites with high shrimp shell loading were observed to exhibit better tensile and impact properties compared to composites with low shrimp shell loading. Moreover, at 8 wt% of SS, the value of tensile strength is comparable to that of neat rP

Effects of Nanographene Addition on Tensile and Electrical Properties of Nylon 6,6 Nanocomposite

The effects of nanographene (NG) filler on tensile and electrical properties of nylon 6,6 nanocomposite were analyzed. The samples were fabricated by blending nylon 6,6/NG in Sino compounder twin screw machine which subsequently injected into standard size specimens for tensile and electrical conductivity test. An addition of small percentages of NG filler, i.e., 0.3, 0.5 and 1.0 wt% significantly affected the tensile performance and electrical conductivity of nylon 6,6 nanocomposite, in which tensile properties and electric conductivity improved with increasing nanographene filler loading

Effects of Particulate Types on Biomass Particulate Filled Kenaf/Polypropylene Composite

The application of natural fibers in composite is very encouraging because of its many benefits such as more environmental friendly and cost reduction. Recently, there is an interest on the application of kenaf-based material for high-end uses such as in automotive industry. In this research, mechanical properties of kenaf fiber reinforced polypropylene (KFRP) composite added with two different types of bio-based fillers, i.e., oil palm shell particle (OPSP) and rubber seed shell particle (RSSP) are studied. The composites were prepared by melt mixing of the materials using internal mixer, followed by compression molding process using hot press machine. The tensile and flexural strength were found to increase with the addition of OPSP as well as RSSP. However, KFRP composite added with RSSP showed better tensile, flexural and impact properties as compared to the composite added with OPSP. From microscopic observation of the raw OPSP and RSSP particles, it was observed that OPSP showed a more granular shape, while RSSP particles were flakier in shape. The difference in particle shape is believed to affect the mechanical properties of the composites as demonstrated in this study

Hygrothermal Effect on Mechanical and Thermal Properties of Filament Wound Hybrid Composite

This study focused on the hygrothermal effect on filament wound glass-carbon/epoxy hybrid composite. Non-geodesic pattern of filament winding with a winding speed of 15.24–30.48 lm/min was used. Fiber tensioning weight of one kg and a winding angle of 30° were created to produce wound samples of the hybrid composite. The hybrid composite was wound by using a ±30° orientation with a total of six layers. Hygrothermal effect was conducted in a humidity chamber for three days (72 h). Control temperatures of 60 and 80°C were established, and humidity percentages of 50%, 70%, and 90% were used. Moisture absorption test showed that heat and humidity in most of the hybrid samples gradually increased. As a result, glass-carbon 80°C/90% showed the highest absorbed moisture at 0.77%. The involvement of highest heat and humidity showed the decline in the values of tensile and flexure strengths at 75.80 and 157.15 MPa, respectively. Fractography analysis using Stereo Microscope Stemi 2000-C indicated that glasscarbon/ epoxy 80°C/90% showed catastrophic damage, large crack, and longest delamination of fiber pullout at 10.39 mm. The fracture criterion revealed that the involvement of heat and humidity significantly affected the mechanical and physical properties of hybrid composite material