EFFECT OF INCREASING NCO/OH MOLAR RATIO ON THE CHEMICAL AND MECHANICAL PROPERTIES OF ISOCYANATE TERMINATED POLYURETHANE PREPOLYMER DERIVED FROM BIO-MASS

2016 ◽  
Vol 2 (2) ◽  
pp. 78-82
Author(s):  
K. Rathika ◽  
S. Begila David
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Castor Oil ◽  
Hard Segment ◽  
Molar Ratio ◽  
Curing Time ◽  
Percent Elongation ◽  
Hard Segment Content ◽  
Polyurethane Film ◽  
Polyurethane Prepolymer

The study deals the effect of increasing NCO/OH molar ratio on the physico-mechanical properties of isocyanate terminated polyurethane prepolymer. The prepolymer was prepared using castor oil and toluene-2,4-diisocyanate. The NCO/OH molar ratio has been varied from 1.6 to 2.0. The formation of the prepolymer was confirmed by UV and FTIR spectroscopy. The results reveal that the curing time of the prepolymer decreased with increase in NCO/OH molar ratio. When NCO/OH molar ratio increased, the tensile strength of the polyurethane film increased, while percent elongation decreased due to increase in hard segment content.

Effect of Castor Oil Impregnation on the Physical and Mechanical Properties of Bacterial Cellulose

2012 ◽  
Vol 3 (1) ◽  
pp. 13-26
Author(s):  
Myrtha Karina ◽  
Lucia Indrarti ◽  
Rike Yudianti ◽  
Indriyati
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Castor Oil ◽  
Young's Modulus ◽  
Physical And Mechanical Properties ◽  
Scanning Electron Micrographs ◽  
Elongation At Break ◽  
Acetone Water

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.

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
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Castor Oil ◽  
High Performance ◽  
Chain Extender ◽  
Coir Fiber ◽  
Percentage Elongation ◽  
Polyurethane Composites ◽  
Performance Character ◽  
Scanning Electron

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.

Transparent composites prepared from bacterial cellulose and castor oil based polyurethane as substrates for flexible OLEDs

2015 ◽  
Vol 3 (44) ◽  
pp. 11581-11588 ◽  
Author(s):  
E. R. P. Pinto ◽  
H. S. Barud ◽  
R. R. Silva ◽  
M. Palmieri ◽  
W. L. Polito ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Bacterial Cellulose ◽  
Young’S Modulus ◽  
Castor Oil ◽  
Young's Modulus ◽  
Visible Region ◽  
Transparent Composites

Flexible and transparent BC/PU composites were prepared, which exhibit excellent transparency (up to 90%) in the visible region and great mechanical properties, with a tensile strength of up to 69 MPa and a Young's modulus of up to 6 GPa.

scholarly journals Karakteristik Bioplastik dari Pati Buah Lindur (Bruguiera gymnorrizha)

2018 ◽  
Vol 7 (1) ◽  
pp. 49-59
Author(s):  
Johan Budiman ◽  
Rodiana Nopianti ◽  
Shanti Dwita Lestari
Keyword(s):  
Mechanical Properties ◽  
Weight Loss ◽  
Tensile Strength ◽  
Degradation Rate ◽  
Water Resistance ◽  
Block Design ◽  
Percent Elongation ◽  
Starch Concentration ◽  
Randomized Block Design ◽  
Biodegradation Test

This research studied the characteristics of bioplastic from large-leafed mangrove (Bruguiera gymnorrizha) starch. This research was arranged used Randomized Block Design (RBD) model, with different starch concentration (0.5%, 1%, 1.5% and 2%) as treatment. The parameters observed were mechanical properties (tensile strength and percent elongation), thickness, water uptake and biodegradation test. The result showed that the starch concentration was not significant, (P>0.05) affected tensile strength and water resistance. Different between treatments was observed as for elongation, thickness and biodegradation test significant (P<0.05). The results obtained from the bioplastic research of large-leafed mangrove starch for tensile strength ranged from 24.59 MPa – 32.91 MPa, percent elongation 2.93% – 4.88%, thickness 0.05 mm – 0,11 mm, water resistance 108.06% – 111.09% and biodegradation test with percent weight loss 17.91% – 54.40% with the highest degradation rate 18.13 – 3.62 mg /15 days burial. The best treatment was obtained by using 1,5% starch, 4 g chitosan and 15% glycerol or equal to starch : chitosan 1.5 g : 4 g and 0.9 mL glycerol.

scholarly journals Effects of Sulfur Curing Systems on Mechanical Properties of NR/SBR Rubber Blends

2019 ◽  
Author(s):  
Ruogu Tang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Abrasion Resistance ◽  
Relative Volume ◽  
Curing Time ◽  
High Modulus ◽  
Elongation At Break ◽  
Tear Strength ◽  
Rubber Blends ◽  
Curing Systems

<div>A series of NR/SBR vulcanizates were prepared by conventional vulcanization (CV), effective vulcanization (EV) and semi-effective vulcanization (SEV) respectively basing on each formulation and optimum curing time. We examined the mechanical properties of NR/SBR vulcanizates including tensile strength, tear strength, elongation at break, modulus, Shore A hardnessand and relative volume abrasion. The results indicated that NR/SBR vulcanizates prepared in different systems differed in mechanical properties. Vulcanizates prepared via CV showed higher tensile and tear strength; vulcanizates prepared via EV had high modulus and hardness, and vulcanizates prepared via SEV performed high abrasion resistance. </div>

scholarly journals Modification of epoxy resins with thermoplastic segmented polycarbonate-based polyurethanes

2014 ◽  
Vol 68 (6) ◽  
pp. 755-765 ◽  
Author(s):  
Jelena Pavlicevic ◽  
Mirjana Jovicic ◽  
Vesna Simendic ◽  
Oskar Bera ◽  
Radmila Radicevic ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Epoxy Resin ◽  
Hard Segment ◽  
Crosslinking Agent ◽  
Polyurethane Elastomers ◽  
Hard Segment Content ◽  
Weight Content ◽  
Epoxy Curing ◽  
Hard Segments ◽  
Modified Epoxy

In this work, epoxy hybrid materials were synthesized by addition of thermoplastic segmented aliphatic polyurethanes with good elastic properties. The modified epoxy samples were obtained by curing of previously homogenized mixture of prepared polyurethane melts, epoxy resin and crosslinking agent Jeffamine D-2000. The influence of different weight content of polyurethanes (5, 10 and 15 wt. % compared to pure epoxy resin) as well the influence of different hard segments of elastomers (20, 25 and 30 wt. %) on the curing of modified epoxy systems was studied. The curing was followed by differential scanning calorimetry (DSC), in dynamic regime from 30 to 300?C, at three heating rates (5, 10 and 20?C/min). With the increase of hard segments content of polyurethanes added in higher concentration (10 and 15 wt. %) into epoxy matrix, the temperature of maximum ratio of curing was shifted to lower values (from 205 to 179?C). Obtained DSC data were analyzed using two integral methods (Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose) and one differential kinetic model (Friedman). The significant differences were observed in the second part of the epoxy curing (for the reaction degrees higher than 60 %), where the values of activation energies remarkably increase. The addition of polyurethane elastomers retarded the curing process due to decreased mobility of reactant molecules caused by higher viscosity of reaction mixture. By detailed analysis of determined kinetic parameters, it is concluded that the influence of slow diffusion is more pronounced in the presence of thermoplastic polycarbonate-based polyurethanes, which confirmed their effect on the mechanism of epoxy curing. The highest tensile strength and hardness showed the DGEBA modified with the polyurethane with highest hard segment content. Increasing the hard segment content of polyurethane and its concentration in matrix, the tensile strength of modified epoxy was increased. The elongation at break of modified epoxy samples was significantly improved by addition of polycarbonate-based polyurethanes with low hard segment content, due to higher content of flexible soft segment chains.

scholarly journals Preparation and modification of natural rubber blends for water purification treatment usage

2020 ◽  
Author(s):  
Wenfa Dong ◽  
Ruogu Tang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Natural Rubber ◽  
Relative Volume ◽  
Curing Time ◽  
Water Industry ◽  
High Modulus ◽  
Elongation At Break ◽  
Tear Strength ◽  
Rubber Blends

<div>The water industry used NR was selected for blending with SBR. A series of NR/SBR vulcanizates were prepared through three different vulcanization systems, conventional vulcanization (CV), effective vulcanization (EV) and semi-effective vulcanization (SEV) respectively, basing on each formulation and optimum curing time. We examined the mechanical properties of NR/SBR vulcanizates including tensile strength, tear strength, elongation at break, modulus, Shore A hardnessand and relative volume abrasion. The results indicated that NR/SBR vulcanizates prepared in different systems differed in mechanical properties. Vulcanizates prepared via CV showed higher tensile and tear strength; vulcanizates prepared via EV had high modulus and hardness, and vulcanizates prepared via SEV performed high abrasion resistance. </div>

scholarly journals Characteristics of Self-Healable Copolymers of Styrene and Eugenol Terminated Polyurethane Prepolymer

Polymers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1674 ◽  
Author(s):  
Jing-Yu Liang ◽  
Se-Ra Shin ◽  
Soo-Hyoung Lee ◽  
Dai-Soo Lee
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Fossil Fuel ◽  
Renewable Resource ◽  
Self Healing ◽  
Elongation At Break ◽  
Good Thermal Stability ◽  
Healing Property ◽  
Polyurethane Prepolymer ◽  
Reversible Nature

With limited biomass that can be currently utilized as a renewable resource, it is important to develop a method to convert biomass into materials that can replace fossil fuel product. In this paper, eugenol, a bio-based allyl chain-substituted guaiacol, was used to synthesize self-healable copolymers. Eugenol terminated polyurethane prepolymer (ETPU) was synthesized from eugenol and polyurethane prepolymers terminated with isocyanate groups. ETPU contained two allyl groups. Self-healing copolymer networks were obtained by copolymerization of ETPU and styrene monomer via free radical polymerization. Effects of ETPU content on the properties of copolymers were then studied. These copolymers containing ETPU exhibited good thermal stability and mechanical properties. These copolymers showed higher tensile strength and elongation at break than PS. Their maximum tensile strength reached 19 MPa. In addition, these copolymers showed self-healing property at elevated temperature due to the reversible nature of urethane units in ETPU.

Effects of Different Size and Shaped Magnesium Particles on the Properties for Fuel Rich Solid Propellant

2013 ◽  
Vol 634-638 ◽  
pp. 1918-1921 ◽  
Author(s):  
Lin Quan Liao ◽  
Wei Qiang Pang ◽  
Hui Xiang Xu ◽  
Yong Hong Li ◽  
Xue Zhong Fan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Rheological Properties ◽  
Burning Rate ◽  
Solid Propellant ◽  
Spherical Particles ◽  
Chemical Characteristics ◽  
Rate Performance ◽  
Percent Elongation ◽  
Lower Viscosity

The physic-chemical characteristics of spherical and coarse magnesium particles were determined. The rheological properties of Mg/HTPB mixtures were investigated. The burning rate performance and mechanical properties of fuel rich propellant were evaluated. The results show that the spherical magnesium particles could be dispersed in the HTPB binder with lower viscosity and yield stress than those of the coarse ones. The burning rate and pressure exponent of propellant with spherical particles increased compared with the coarse ones, and the percent elongation is much higher than that of coarse one, whereas, the tensile strength shows reverse.

Development of Hypereutectoid Steel with Nodular Graphite

2010 ◽  
Vol 457 ◽  
pp. 132-136
Author(s):  
Dmytry S. Kozak
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Impact Strength ◽  
Yield Strength ◽  
Brinell Hardness ◽  
Hypereutectoid Steel ◽  
Percent Elongation ◽  
Nodular Graphite ◽  
Free Cementite

This work studies the formation of cast structures in hypereutectoid steel modified by alloying modifiers (Fe30Si55Mg7Ca2REM4, Fe34Si55Mg9Ca2 and Fe63Ni30Mg7) together with inoculants Fe20Si60Ba20. It is found that at spheroidizing by 0.7 % Fe63Ni30Mg7 and inoculation by 1.5 % Fe20Si60Ba20 causes the formation of inclusions of nodular graphite with nodularity exceeding 90 % and a structurally-free cementite structure is obtained. The mechanical properties of the steel with nodular graphite modified by Fe63Ni30Mg7 and Fe20Si60Ba20 are as follows: tensile strength (σb) 660-680 МPа, yield strength (σ0.2) 520-540 МPа, percent elongation (δ) 5-8 %, impact strength (КС) 15-35 J/cm2, Brinell hardness (НВ) 241-255. After ferritic annealing these parameters were found to be σb =530-560 МPа, σ0.2=400-430 МPа, δ =20-24 %, КС=160- 180 J/cm2, 150-162 НВ.

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