PREPARATION OF CHAIN EXTENDED POLYURETHANE AND ITS COMPOSITES BASED ON CASTOR OIL AND COIR FIBER

2015 ◽  
Vol 1 (01) ◽  
pp. 67-70
Author(s):  
A. Malar Retna

The chain extended polyurethane was synthesized by reacting castor oil based polyol with 4,4’-methylenebis(cyclohexyl) isocyanate and chain extender such as malonic acid. The composites have been fabricated by incorporating the coir fiber into the neat polyurethane. The polyurethane and its composites were characterized with respect to their mechanical properties such as hardness, tensile strength, percentage elongation and Young’s modulus. The morphology of neat polyurethane and its composites with coir fiber was studied using scanning electron microscope (SEM). These studies revealed the high performance character of the polyurethane composites with respect to the corresponding neat polyurethane.

2014 ◽  
Vol 1611 ◽  
pp. 95-104 ◽  
Author(s):  
Nadira Mathura ◽  
Duncan Cree ◽  
Ryan P. Mulligan

ABSTRACTIn many tropical countries coconut (coir) fiber production is a major source of income for rural communities. The Caribbean has an abundance of coconuts but research into utilizing its by-products is limited. Environmentally friendly coir fibers are natural polymers generally discarded as waste material in this region. Research has shown that coir fiber from other parts of the world has successfully been recycled. This paper therefore investigates the mechanical properties of Caribbean coir fiber for potential applications in civil engineering.Approximately four hundred fibers were randomly taken from a coir fiber stack and subjected to retting in both distilled and saline water media. The mechanical properties of both the retted and unretted coir fibers were evaluated at weekly increments for a period of 3 months. Tensile strength test, x-ray diffraction analysis and scanning electron micrographs were used to assess trends and relationships between fiber gauge lengths, diameter, tensile strength and Young’s modulus. Diameters ranged between 0.11 mm-0.46 mm, while fiber samples were no longer than 250 mm in length. The tensile strength and strain at break decreased as the gauge length increased for both unretted and retted fibers. The opposite occurred for the relationship between the gauge length and Young’s modulus. Additionally, the tensile strength and modulus decreased as the fiber diameter increased. Neither distilled nor saline water improved the coir fiber’s crystalline index. Scanning electron micrographs qualitatively assessed fiber surfaces and captured necking and microfibril degradation at the fractured ends.The analysis revealed that the tensile strength, modulus, strain at break and crystallinity properties of the Caribbean coir fibers were comparable to commercially available coir fiber which are currently being used in many building applications.


2017 ◽  
Vol 10 (1) ◽  
pp. 61-64
Author(s):  
SMG Moktadir ◽  
MU Talukder ◽  
AKO Huq ◽  
MA Gafur ◽  
AMS Chowdhury

Coir fiber (CF) reinforced polypropylene (PP) composites were fabricated using an extruder machine. The fiber contents were varied 5 to 20% and physico-mechanical properties as well as bio-degradability were also tested. Ultimate tensile strength and flexural strength decreases with the increases of percentages of fiber addition. Lowest percentage elongation is observed at 20% CF+PP composite which are rigid in nature. Leeb rebound hardness also decreases with the increase of percentage of raw fiber addition. The bio-degradation of different percentage of CF and PP composites in soil and saline water increased with increase of coir fiber content. Thus, it showed that higher percentage of coir fiber was produced more biodegradable and eco-friendly byproducts. However, higher percentages of coir fiber decrease the mechanical properties. A moderate percentage of coir fiber i.e. 15% CF +PP showed the good mechanical properties as well as considerable amount of bio-degradability in soil and saline water.J. Environ. Sci. & Natural Resources, 10(1): 61-64 2017


2010 ◽  
Vol 123-125 ◽  
pp. 391-394 ◽  
Author(s):  
T.M. Mruthyunjaya Swamy ◽  
Manjula Koregala Sidde Gowda ◽  
Siddaramaiah ◽  
Joong Hee Lee

Composites of silk fibre reinforced chain extended polyurethane (CEPU) was synthesized by the reaction of castor oil with different diisocyanates and glutaric acid as chain extender. The effect of incorporation of silk fibre into neat CEPU on the physico- mechanical properties and thermal behaviours (TGA and DMA) has been investigated. The incorporation of silk fibre into CEPUs resulted in an enhancement of tensile strength and Tg. The effects of biological fluids and salt solution on swelling behavior of CEPU biocomposites were reported. Key words: Castor oil, silk fibre, composites, polyurethane, DMA, TGA.


2012 ◽  
Vol 85 (1) ◽  
pp. 120-131 ◽  
Author(s):  
Md. Najib Alam ◽  
Swapan Kumar Mandal ◽  
Subhas Chandra Debnath

Abstract Several zinc dithiocarbamates (ZDCs) as accelerator derived from safe amine has been exclusively studied in the presence of thiazole-based accelerators to introduce safe dithiocarbamate in the vulcanization of natural rubber. Comparison has been made between conventional unsafe zinc dimethyldithiocarbamate (ZDMC) with safe novel ZDC combined with thizole-based accelerators in the light of mechanical properties. The study reveals that thiuram disulfide and 2-mercaptobenzothiazole (MBT) are always formed from the reaction either between ZDC and dibenzothiazyledisulfide (MBTS) or between ZDC and N-cyclohexyl-2-benzothiazole sulfenamide (CBS). It has been conclusively proved that MBT generated from MBTS or CBS reacts with ZDC and produces tetramethylthiuram disulfide. The observed synergistic activity has been discussed based on the cure and physical data and explained through the results based on high-performance liquid chromatography and a reaction mechanism. Synergistic activity is observed in all binary systems studied. The highest tensile strength is observed in the zinc (N-benzyl piperazino) dithiocarbamate-accelerated system at 3:6 mM ratios. In respect of tensile strength and modulus value, unsafe ZDMC can be successfully replaced by safe ZDCs in combination with thiazole group containing accelerator.


Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2174
Author(s):  
Diana Gregor-Svetec ◽  
Mirjam Leskovšek ◽  
Blaž Leskovar ◽  
Urška Stanković Elesini ◽  
Urška Vrabič-Brodnjak

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.


2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati

The effect of castor oil on the physical and mechanical properties of bacterial cellulose is described. Bacterial cellulose (BC) was impregnated with 0.5–2% (w/v) castor oil (CO) in acetone–water, providing BCCO films. Scanning electron micrographs revealed that the castor oil penetrated the pores of the bacterial cellulose, resulting in a smoother morphology and enhanced hydrophilicity. Castor oil caused a slight change in crystallinity indices and resulted in reduced tensile strength and Young's modulus but increased elongation at break. A significant reduction in tensile strength and Young's modulus was achieved in BCCO films with 2% castor oil, and there was an improvement in elongation at break and hydrophilicity. Impregnation with castor oil, a biodegradable and safe plasticiser, resulted in less rigid and more ductile composites.


2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chatree Homkhiew ◽  
Surasit Rawangwong ◽  
Worapong Boonchouytan ◽  
Wiriya Thongruang ◽  
Thanate Ratanawilai

The aim of this work is to investigate the effects of rubberwood sawdust (RWS) size and content as well as the ratio of natural rubber (NR)/high-density polyethylene (HDPE) blend on properties of RWS reinforced thermoplastic natural rubber (TPNR) composites. The addition of RWS about 30–50 wt% improved the modulus of the rupture and tensile strength of TPNR composites blending with NR/HDPE ratios of 60/40 and 50/50. TPNR composites reinforced with RWS 80 mesh yielded better tensile strength and modulus of rupture than the composites with RWS 40 mesh. The TPNR/RWS composites with larger HDPE content gave higher tensile, flexural, and Shore hardness properties and thermal stability as well as lower water absorption. The TPNR/RWS composites with larger plastic content were therefore suggested for applications requiring high performance of thermal, physical, and mechanical properties.


2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fakhim Babak ◽  
Hassani Abolfazl ◽  
Rashidi Alimorad ◽  
Ghodousi Parviz

We investigate the performance of graphene oxide (GO) in improving mechanical properties of cement composites. A polycarboxylate superplasticizer was used to improve the dispersion of GO flakes in the cement. The mechanical strength of graphene-cement nanocomposites containing 0.1–2 wt% GO and 0.5 wt% superplasticizer was measured and compared with that of cement prepared without GO. We found that the tensile strength of the cement mortar increased with GO content, reaching 1.5%, a 48% increase in tensile strength. Ultra high-resolution field emission scanning electron microscopy (FE-SEM) used to observe the fracture surface of samples containing 1.5 wt% GO indicated that the nano-GO flakes were well dispersed in the matrix, and no aggregates were observed. FE-SEM observation also revealed good bonding between the GO surfaces and the surrounding cement matrix. In addition, XRD diffraction data showed growth of the calcium silicate hydrates (C-S-H) gels in GO cement mortar compared with the normal cement mortar.


2018 ◽  
Vol 186 ◽  
pp. 02001
Author(s):  
Teng-wei Zhu ◽  
Cheng-liang Miao ◽  
Zheng Cheng ◽  
Zhipeng Wang ◽  
Yang Cui ◽  
...  

The influence of the mechanical properties of X70 pipeline steel under different annealing temperature was studied. The corresponding microstructure was investigated by the Field Emission Scanning Electron Microscopy. The results showed that the yield strength and the tensile strength both experienced from rise to decline with the increase of annealing temperature. The grain sizes were coarse and a large amount of cementite precipitated due to preserving temperature above 550 °, which induced matrix fragmentation and deteriorate the -10 ° DWTT Toughness. There were little changes on the microstructure and mechanical properties when the annealing temperature was under 500 °.


2016 ◽  
Vol 850 ◽  
pp. 511-518 ◽  
Author(s):  
Hai Jun Liu ◽  
Lie Jun Li ◽  
Jian Wei Niu ◽  
Ji Xiang Gao ◽  
Chuan Dong Ren

The effects of Mg and Cu additions with different contents on the mechanical properties of Al-Si alloy prepared by indirect squeeze casting have been experimentally investigated. The microstructure and mechanical properties of as-cast and T6-treated Al-Si-Cu-Mg alloys were tested by OM, SEM, DSC and tensile measurement, where the samples were produced by artificial aging at 180°C for 8 h after solution treatment at 540°C for 4 h. It has been found that for the as-cast alloys, with increasing contents of Mg and Cu the tensile strength (UTS) and yield strength (YS) increased, while the percentage elongation (El) decreased. And the optimal mechanical properties of Al-Si-Cu-Mg alloys were obtained under the content ratio of Cu/Mg within 4, where the UTS and El reached 426 MPa and 6.3% after T6 treated, respectively.


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