Preparation,properties and application of tamarind seed gum reinforced banana fibre composite materials

Technology has been developed to prepare a biodegradable and environmental friendly composite material from tamarind seed gum and banana fibre. Tamarind seed gum is prepared from the endosperm of roasted seeds of the tamarind tree. The different temperature condition maintained for roasting the seeds are 130, 160, and 180°C. Banana fibres are extracted from different varieties of banana trees, which are used for the preparation of composite material. The tensile strength of the composite material is measured and shows dependency on the variety of banana fibre used in the preparation and also the roasting temperature condition of the tamarind seed. Tamarind seed gum (the seed roasted at the temperature condition of 130°C) and Red banana fibre composite shows the highest tensile strength of 3.97 MPa and Poovan fibre composites shows the lowest tensile strength of 1.90 MPa. The composite material of other varieties shows tensile strength in between these two values. The percentage of moisture absorption of the composite material has a direct correlation to the tensile strength. In addition, investigation on fire retardant test of tamarind seed gum — banana fibre composite material revealed that untreated and varnish coated banana fibre composite material has good fire retardant characteristics. This is an important feature to promote the use of this composite material as a false roofing material instead of thermocole.     

Elasticity, microstructure and thermal stability of foliage and fruit fibres from four tropical crops

A comparative analysis of the elasticity, microstructure and thermal stability of fibres (thickness ranging from 43.4 to 189.4 µm) isolated from pineapple leaves (PALF), coconut coir (COIR), banana leaf-stem (BAN) and oil palm empty fruit bunch (OPEFB) reported in this study. Statistical analysis of the mechanical properties derived from tensile test to rupture reveals significant differences (P<0.05) in the fibre strength (σ), stiffness (E) and extensibility (parameterized by the strain to rupture, ?). It is observed that COIR fibres yield the smallest strength, σ (=99.8±22.5 MPa), and stiffness, E (= 0.5±0.1 GPa), while PALF fibres yield the largest σ (=639.5±301.6 MPa) and E (=7.1±3.1 GPa); PALF fibres exhibit the smallest ? (=0.11±0.03) but OPEFB fibres yield the largest ? (=2.0±1.3). From scanning electron micrographs, it is observed that cellulose fibril rupture predominates in OPEFB, COIR and BAN fibres; a large proportion of the cellulose fibrils fail by pullout in PALF fibres. Thermogravimetric analysis reveals that all fibres are thermally stable up to 250 °C; the fibre residue ranges from 30 to 80 wt% after heating to 500 °C. In particular, BAN experiences the highest weight loss and PALF experiences the lowest weight loss. The findings lend to a simple approach for determining the performance of the composites by assessing the type of natural fibres for reinforcing polymeric matrices.     

The effect of temperature and water on the mechanical properties of wool fibres investigated with different experimental methods

The tensile and durability properties of single wool fibres were investigated with tensile testing method and lever equipment giving the results examined by Zhurkov’s kinetic equation under the effects of temperatures and water. Moreover, Differential Scanning Calorimetry (DSC) method was applied to determine denaturation and degradation peaks and corresponding enthalpies of wool fibre. It was shown that with increasing temperature, tensile properties and durability of the wool fibres decreased considerably. A great decrease on tensile properties was seen at temperatures higher than ∼200 °C after which a denaturation doublet of α-keratin and a wide thermal degradation peak were observed in DSC diagrams. Moreover, the wet fibres obtained lower tensile characteristics except breaking extension which increased by 9 % and 20 % for the fibres kept in water for one h and one month, respectively. However, the breaking extension of the fibre tested in water increased greatly by 73 % which indicates the important role of water molecules on the intermolecular interactions during stretching. The weakening effect of water molecules on the structure was also shown by DSC result of wet wool fibres at which the thermal degradation enthalpy of α-keratin and other histological components decreased by 22 %. The changes of the tensile and durability characteristics of wool fibres were compared and discussed in detail based on Zhurkov’s equation and intermolecular interactions.     

Influence of fibre contents on mechanical and thermal properties of roselle fibre reinforced polyurethane composites

The aim of this paper is to study the effect of fibre content on mechanical and morphological properties and thermal stability of roselle fibres (RFs) reinforced polyurethane (TPU) composites. The RF/TPU composites were prepared at difference fibre contents; 10, 20, 30, 40 and 50 wt% by melt mixed mixer and hot press at 170 °C. Mechanical (tensile, flexural and impact strength) and Thermogravimetric analysis (TGA) properties of RF/TPU composites were measured according to ASTM standard. Obtained results indicated that effect of fibre contents display improved tensile and flexural and impact strength properties. RF/TPU composites show the best mechanical and thermal properties at 40 wt% roselle fibre content. Scanning electron microscopy (SEM) micrograph of fractured tensile sample of the roselle composite revealed good fibre/matrix bonding. TGA showed that RF/TPU with difference fibre contents had improved thermal stability.     

Effect of processing route on the composition and properties of hemp fibre

There is great interest in the plant Cannabis sativa (hemp) as a source of technical fibres for the reinforcement of polymers in composite materials due to its high mechanical properties. In this work, the effect of enzymatic, hydrothermal and alkaline treatments on the composition and mechanical properties of hemp fibre are compared. The influence of enzyme concentration and treatment time was examined (2.5–80 % Pectinex® Ultra SP-L, 6–48 hrs). Additionally, hydrothermal (170 °C, 10 bars) and alkaline treatments (18 wt. % NaOH, 40 °C) were used as pre-treatments to observe their effect on subsequent enzymatic treatment. The composition of hemp fibre was analysed by wet chemistry and Fourier transform infrared spectroscopy, while microstructure and mechanical properties were examined by scanning electron microscopy and tensile testing, respectively. Enzymatic treatment resulted in extensive fibrillation and removal of non-cellulosic components, especially when combined with hydrothermal treatment. However, a lengthy enzymatic treatment or combinative enzymatic-alkaline treatment led to extensive fibre breakdown that was accompanied by a pronounced reduction in the mechanical properties. Enzymatic treatment decreased Young’s modulus and tensile strength by 77 and 73 % respectively, and alkaline treatment by 83 and 36 %. The hydrothermal treatment resulted in only minor changes in these properties.     

The effect of gelation and curing temperatures on mechanical properties of pultruded kenaf fibre reinforced vinyl ester composites

Process parameters such as gelation and curing temperatures are parameters that influence the pultruded kenaf reinforced vinyl ester composites profile quality and performance. The effect of gelation and curing temperatures on mechanical (tensile, flexural and compression properties) and morphological properties of pultruded kenaf reinforced vinyl ester composites were analyzed. Obtained results indicated that increase of gelation and curing temperatures during the pultrusion process of kenaf reinforced vinyl ester composites influenced the mechanical properties of the composites. When the gelation and curing temperatures were increased, tensile strength, tensile modulus, flexural strength, flexural modulus and compressive strength were affected and they were either increased or decreased. The factors that influenced these results include improper curing, excessive curing, water diffusion, and the problems associated with interfacial bonding between fibre and matrices. The optimum values of the tensile strength for gelation and curing temperatures of kenaf pultruded composites were at 100 °C and 140 °C, tensile modulus at 80 °C and 180 °C, flexural strength at 100 ° and 140 °, flexural modulus at 120 ° and 180 °, and compressive strength at 120 °C and 180 °C, respectively. The scanning electron micrographs of tensile fractured samples clearly show that with the increase in gelation temperature, it creates the lumens between matrix and kenaf fibre thus reducing tensile properties whereas increasing the curing temperature caused less fibre pull out and enhanced fibre/matrix interfacial bonding.     

A preliminary evaluation of matricaria maritimum fibres for polymer reinforcement

This short communication describes results from a preliminary characterization of the dimensions and mechanical properties of matricaria maritimum fibres. The aim is to develop a complementary industrial application of these plants, which are grown along the coast mainly for pharmaceutical use. The fibres are shown to be of small diameter, 5-10 μm, and tubular in form. Nano-indentation on fibres and tensile tests on fibre bundles provide an indication of the mechanical behaviour of these fibres, which are similar to those of sisal (leaf fibre) and miscanthus (grass fibre), and may be interesting for reinforcement of polymer matrix composites.     

Green composites. I. physical properties of ramie fibers for environment-friendly green composites

The surface topography, tensile properties, and thermal properties of ramie fibers were investigated as reinforcement for fully biodegradable and environmental-friendly ‘green’ composites. SEM micrographs of a longitudinal and cross-sectional view of a single ramie fiber showed a fibrillar structure and rough surface with irregular cross-section, which is considered to provide good interfacial adhesion with polymer resin in composites. An average tensile strength, Young’s modulus, and fracture strain of ramie fibers were measured to be 627 MPa, 31.8 GPa, and 2.7 %, respectively. The specific tensile properties of the ramie fiber calculated per unit density were found to be comparable to those of E-glass fibers. Ramie fibers exhibited good thermal stability after aging up to 160°C with no decrease in tensile strength or Young’s modulus. However, at temperatures higher than 160°C the tensile strength decreased significantly and its fracture behavior was also affected. The moisture content of the ramie fiber was 9.9%. These properties make ramie fibers suitable as reinforcement for ‘green’ composites. Also, the green composites can be fabricated at temperatures up to 160°C without reducing the fiber properties.     

An effective and simple process for obtaining high strength silkworm (Bombyx mori) silk fiber

This article describes a new process for strengthening natural silk fibers. This process is simple yet effective for mass production of high strength silk fibers, enabled by drawing at a lower temperature and immediately heat setting at a higher temperature. The processing conditions were investigated and optimized to improve the strength. Silk fibers drawn to the maximum ratio at room temperature and then heat set at 200 °C show best tensile properties. Some salient features of the resulting fibers are tensile strength at break reaching 533±10.2 MPa and Young’s modulus attaining 12.9±0.57 GPa. These values are significantly higher than those of natural silk fibers (tensile strength increased by 44 % and Young’s modulus by 135 %). Wide-angle X-ray diffraction and FTIR confirm the transformation of silk I to silk II crystalline structure for the fiber obtained from this process. DSC and TGA data also provide support for the structural change of the silk fiber.     

Mechanical behavior of composites reinforced with fibers caroa

Composites were prepared with 13, 23 30 and 40 % fiber and evaluated the mechanical performance in tensile, flexural and impact. The mechanical properties of these composites were also evaluated function of time at 110 °C thermal exposure. Caroa fibers were characterized by techniques such as thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the best mechanical properties were achieved for composites containing 23 to 30 % fiber. The incorporation of 23 % fiber caroa increased both the modulus of elasticity in the tensile test as the flexural strength and impact, the composite with 30 % fiber caroa showed higher tensile strength. The results show that the tensile and flexural strength of the composite decreased with time of thermal exposure. The thermal aging at 110 °C caused a decrease in tensile properties of the composites.     

Comparison of composites made from fungal defibrated hemp with composites of traditional hemp yarn

Aligned epoxy-matrix composites were made from hemp fibres defibrated with the fungi Phlebia radiata Cel 26 and Ceriporiopsis subvermispora previously used for biopulping of wood. The fibres produced by cultivation of P. radiata Cel 26 were more cellulose rich (78%, w/w) than water-retted hemp due to more degradation of pectin and lignin. The defibrated hemp fibres had higher fibre stiffness (88–94 GPa) than the hemp yarn (60 GPa), which the fibre twisting in hemp yarn might explain. Even though mild processing was applied, the obtained fibre strength (643 MPa) was similar to the strength of traditionally produced hemp yarn (677 MPa). The fibre strength and stiffness properties are derived from composite data using the rule of mixtures model. The fibre tensile strength increased linearly with cellulose content to 850 MPa for pure cellulose. The fibre stiffness increased also versus the cellulose content and cellulose crystallinity and reached a value of 125 GPa for pure crystalline cellulose.     

Effect of hollow polyester fibres on mechanical properties of knitted wool/polyester fabrics

The physical and mechanical characteristics of hollow polyester fibres were compared with solid polyester fibres in order to establish their processing behaviour and performance characteristics. The effects of hollow fibres on fabric properties were investigated by using microscopy and tests of tensile and bursting strength, pilling, abrasion resistance, water vapour permeability, and handle. The results show that tensile strength of hollow polyester fibres and yarns are negatively affected by the cavity inside the fibre. Hollow fibres also have higher stiffness and resistance to bending at relaxed state. Fabrics made from hollow polyester/wool blends and pure wool fabrics show three distinguishable steps in pilling. During pilling, hollow fibres break before being pulled fully out of the structure, leading to shorter protruding fibres. Microscopy studies showed that the breakdown of hollow fibres started during entanglement by splitting along the helical lines between fibrils. KES results showed that the friction between fibres and the fibre shape are the most important parameters that determine the fabric low stress mechanical properties. However, in some aspects, the hollow structure of the fibre does not have a significant effect.     

Analysis of green hemp fibre reinforced composites using bag retting and white rot fungal treatments

The main objective of this project was to investigate two low cost treatment methods, namely bag retting and treatment with white rot fungi, which could be applied to hemp fibre with low environmental impact to improve its interfacial bonding with polypropylene. Wet chemical analysis, FTIR, scanning electron microscopy (SEM), X-ray diffraction (XRD), zeta potential and single fibre tensile testing were used to characterise the effect of treatment on hemp fibres. It was found that all the treatments increased the tensile strength of composites. White rot fungi Schizophyllum commune (S.com) treated fibre composites had the highest tensile strength of 45 MPa, an increase of 28% compared to composites using untreated fibre.     

Preparation,structure and properties of boron modified high-ortho phenolic fibers

Boron modified high-ortho phenolic fibers (o-BPFs) were prepared by melt-spinning from boron modified highortho phenolic resins (o-BPRs) with the weight-average molecular weight of 4973 g/mol, followed by being cured in a solution of formaldehyde and hydrochloric, and then heat-treated under high temperature. Gel permeation chromatography (GPC) and nuclear magnetic resonance spectroscopy (NMR) were used to measure the average molecular weight and ortho/para (o/p) ratio of o-BPRs. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the chemical and morphological structures of o-BPRs and o-BPFs. Thermogravimetric analysis (TGA) was employed to examine the thermal stability properties of different resins and fibers and the tensile strength of fibers was measured by a tensile tester. It was found that under proper curing and heat-treatment conditions, the tensile strength of o-BPFs reached 213.6 MPa and the char yield in N₂ atmosphere at 800 °C attained 75.4 %. Compared with phenolic fibers (PFs), the decomposition temperatures at 5 % weight loss of o-BPFs in N₂ and air atmospheres were increased by 156.8 °C and 219.0 °C, respectively.     

Characterization of light weight epoxy composites from short Sansevieria Cylindrica fibers

Sansevieria (genus) cylindrica (species) belongs to Agavaceae family plant fiber first time used as a reinforcing agent in the epoxy system. Fibre extracted from leaves, fairly lesser density, porosity, higher strength to weight ratio (hereafter called SCF) and these fibers were alkali-treated and yet impregnated on the epoxy system using wet hand lay up technique in order to compare with untreated fiber on performance. DMA, TGA, DSC, FTIR, SEM, degradation temperature, flexural and tensile tests were performed for untreated and alkali-treated epoxy composites using different SCF volumes viz. 1 vol.%, 5 vol.%, 7 vol.% and 9 vol.%. Alkali treated fibre were found to have higher initial and final degradation temperatures and flexural and tensile strength. The removal of the amorphous hemi-cellulose on alkali treatment was played an instrumental in improving properties. A 3 °C increase in glass transition temperature and decomposition temperature were recorded respectively and over all treated SCF composites reinforced on the epoxy were shown significant results than untreated. Storage modulus and tan ?? were observed well at 9 vol.% treated SCF while flexural and tensile were increased by 35 and 13 % for SCF treated composites respectively.     

Mechanical and physical properties of expanded starch, reinforced by natural fibres

Biodegradable foams made from potato starch and natural fibres were obtained by extrusion. The effects of varying origins of these fibres on foam properties were studied, as well the relationships between their properties and the foam microstructure. The addition of fibres increased the expansion index and led to a significant reduction in water adsorption of starch foams, generally improving foam properties. The mechanical properties of the foams were affected by both relative humidity (RH) of storage and foam formulation. In general, as the RH increased, the foam strength decreased. The formulation presenting the best mechanical properties contained 10 wt% hemp fibre and had a maximal resistance of 4.14 MPa and a modulus of 228 MPa, corresponding to a more compact and dense microstructure.     

Effects of plasticizer on the mechanical properties of kenaf/starch bio-composites

Research and development of biodegradable bio-composite can replacement the synthetic polymer materials, which is used for automobile interior materials, finishing materials of air conditioner and refrigerator. To develop both components as biodegradable bio-composite, this research used natural polymer starch as matrix and kenaf fiber as a filler. Various plasticizer(polyvinyl alcohol, polyethylene glycol, glycerol) were added and examined the mechanical properties of the kenaf/starch bio-composites according to these plasticizer. The kenaf bast which cultivated in Korea was retted with 2 % NaOH solution. The plasticizer weighting 10 % of that of matrix was added. kenaf/starch composites were molded with hot press for 30 minutes at 130 °C and 3,500 PSI molding condition. The mechanical properties such as tensile strength, elongation, and young modulus of the kenaf/starch composites were measured. Also, we measured the SEM cross-section images in order to investigate interfacial adhesion properties of fractured surfaces. The order of strength size of composites were G (12.42 MPa) > PVA (9.72 MPa) > PEG (4.73 MPa) samples respectively. The tensile strength of PEG sample is lower than the control sample (5.40 MPa).     

Effects of Drawing and Heat-Treatment Conditions on the Structure and Mechanical Properties of Polyhydroxyamide and Polybenzoxazole Fibers

We report the preparation of polybenzoxazole (PBO) fiber from polyhydroxyamide (PHA) precursor fiber which is free from strong acid such as polyphosphoric acid. We prepared the PHA fibers with different spin-draw ratios (SDRs) using a wet-spinning method and the PBO fibers with an SDR of 3.5 (SDR-3.5 PBO fibers) were prepared by various heat-treatment temperatures, and investigated their morphology, crystalline structure, and mechanical properties. The simultaneous thermogravimetric analysis-mass spectrometry (STA-MS) and field-emission scanning electron microscopy (FE-SEM) results confirmed that the diameter of the SDR-3.5 PBO fiber was much smaller than that of the SDR-3.5 PHA fiber, due to the release of water during the thermal cyclization reaction which forms the PBO structure. The wide-angle Xray diffraction (WAXD) pattern of the SDR-3.5 PBO fiber heat-treated at 350 °C (SDR-3.5 PBO 350 fiber) showed two peaks, at 2θ=14.83 ° and 24.38 °, and the diffraction angles dropped with increasing heat-treatment temperature. In addition, the initial modulus and tensile strength of the SDR-3.5 PBO fiber heat-treated at 550 °C (SDR-3.5 PBO 550 fiber) were found to be 19.1 GPa and 449.2 MPa, which were much higher than those of the SDR-3.5 PHA fiber, 9.3 GPa and 227.0 MPa, respectively.     

Improvement of thermo-mechanical properties of basalt fiber using heat resistant polymeric coatings

Heat resistant coatings of textile materials are required so that they can fulfill the high security demand in the case of resistance to fire and improve thermo-mechanical properties. These coatings also enhance the interface properties of textiles in the composites. Liquid phase coatings, based on polysilazane and polysiloxane polymers were deposited onto the basalt fiber (BF) yarn using impregnation coating method. Tensile testing under thermal stress was conducted to examine the thermo-mechanical properties of both coated and uncoated yarns. The thermo-mechanical study indicated that the heat resistant coatings enhanced 40–70 % tensile strength and 25–40 % stiffness of original BF yarns up to 400 °C. BF yarn retained 65–90 % of its tensile strength at 500 °C due to coatings, whereas the uncoated BF yarn lost 85 % strength at this temperature. Thermo gravimetric analysis (TGA) showed that the coatings have good thermal stability. In addition, scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, optical microscopy and fourier transform infrared (FTIR) spectroscopy analyses were executed in order to evaluate the surface microstructure as well as surface chemical compositions of the BF yarns.     

Structure and performance of fibers prepared from liquefied wood in phenol

The fibers from liquefied wood in phenol (WPFs) were spun by adding hexamethylenetetramine as synthetics and cured by soaking in solution containing hydrochloric acid and formaldehyde as main components. The chemical structure of WPFs remarkably changed from that of liquefied wood was identified by FT-IR spectrometer. WPFs with the average diameter of 27∼42 μm, tensile strength of 230∼356 MPa, and modulus of 15∼31 GPa were obtained using spinning speed of 0.72 μm min⁻¹, hydrochloric acid concentration of 18.5 %, heating rate of 10 °C h⁻¹, and curing time of 4 h. These WPFs showed a high thermal stability and a complex thermal decomposition process by TG(thermogravimetric) analysis. It was also found that the two obvious weight loss temperatures of WPFs were 510°C and 748°C.