MECHANICAL PROPERTIES AND CURE TEST OF A NATURAL RUBBER/POLY(VINYL ALCOHOL) BLEND

2012 ◽  
Vol 85 (1) ◽  
pp. 147-156 ◽  
Author(s):  
Sa-Ad Riyajan ◽  
Suwit Chaiponban ◽  
Sasitorn Chusri ◽  
Supayang Piyawan Voravuthikunchai

Abstract Properties and antibacterial activity of polymer blend films prepared from polyvinyl alcohol (PVA) and natural rubber (NR) blends, in the presence of maleic acid as a cross-linking agent were studied. The effect of the maleic acid content, curing temperature, and curing time on the properties of the polymer blend was investigated. Cross-linking between PVA and maleic acid was observed by attenuated total reflection mode–Fourier transform infrared spectroscopy at 1152 cm−1. The swelling ratio of the polymer blend decreased as a function of the increase of the maleic acid content. The tensile strength of the polymer blend increased with an increase of both the maleic acid and the curing time. The highest tensile strength of the samples was observed with 40% w/w maleic acid after a 24 h curing time at 120 °C. The elongation at the break of 60/40 NR/PVA was ∼500% at 120 °C for 1 h. In addition, the polymer blend showed good antibacterial activity with Staphylococcus aureus ATCC25923, Escherichia coli ATCC25922, and Acinetobacter baumannii JVC 1053 and could find many applications.

2012 ◽  
Vol 482-484 ◽  
pp. 1294-1297
Author(s):  
Dian Wei Zhang ◽  
Yong Zhu Cui ◽  
Yan Ling Sui

In this paper, fluorinated water and oil repellent finishing agent was mixed with auxiliary agents and the durability of fabrics treated with the finishing agent was investigated. The water and oil repellent property was discussed and evaluated by contact angle method. The results showed that under the same conditions, adding 0.4% cross-linking agent could make the contact angle of the treated fabric higher than untreated, and the durable-washing property of the fabric was excellent and the durability of fluorinated water and oil repellent finishing agent got improved greatly. The optimum process was that the dosage of water and oil repellent finishing agent was 50g/L, the dosage of cross-linking agent was 4g/L, curing temperature was 160 °C and curing time was 90s.


2014 ◽  
Vol 997 ◽  
pp. 239-242
Author(s):  
Guang Lu ◽  
He Ping Yu ◽  
Yong Zhou Wang ◽  
Yong Yue Luo ◽  
Zong Qiang Zeng

After a maturation of three days at ambient temperature, the sulfur-prevulcanized natural rubber latex (SNRL) was stabilized by 20wt% Peregal O, and then acidified with the 36wt% acetic acid by a ratio of 5, 15, 25, 35 and 45 g of 36wt% acetic acid to 100g SNRL, to obtain acidified prevulcanized NR latex (ASNRL) with different acidity, respectively. The viscosity of ASNRL increased, while the nitrogen content decreased, with the increment of acetic acid content and the decrease in pH; for unaged samples, the tensile strength, elongation at break, 300% and 500% moduli of the ASNRL films were only slightly lower than those of SNRL film; however the hot-air aging resistance decreased with the increment of acetic acid content.


2013 ◽  
Vol 773 ◽  
pp. 668-672
Author(s):  
Jun Liang Liu ◽  
Ping Liu ◽  
Xiao Qiang Tang ◽  
Dong Zeng ◽  
Xing Kai Zhang ◽  
...  

In this paper, the blends of natural rubber with waste ground rubber powders have been prepared by mechano-chemical activation method. The influences of particle sizes on both processing performances and mechanical properties have been investigated. The results indicated that: the blends with waste ground rubber powders of smaller particle sizes approached to higher surface tensile and easily mechano-chemical activation, which led to the formation of complete homogenous re-vulcanization cross-linking structure and resulted in the improvements of the whole performances of the final products. The tensile strength, the elongation at break and tear strength approached to the highest value of 20.7MPa, 530% and 33.0 kN/m as the 100mesh waste ground rubber powders were used as the starting materials.


2020 ◽  
Author(s):  
Wenfa Dong ◽  
Ruogu Tang

<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>


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4067
Author(s):  
Ioanna Tzoumani ◽  
Georgia Ch. Lainioti ◽  
Alexios J. Aletras ◽  
Gabriel Zainescu ◽  
Simina Stefan ◽  
...  

Novel cross-linked hydrogels were synthesized as potential materials for the development of smart biofertilizers. For this purpose, hydrogels were prepared using collagen hydrolysate recovered from tannery waste. The water-soluble polymer poly(sodium 4-styrenesulfonate-co-glycidyl methacrylate) (P(SSNa-co-GMAx)) was among others used for the cross-linking reaction that combined hydrophilic nature with epoxide groups. The synthetic procedure was thoroughly investigated in order to ensure high percentage of epoxide groups in combination with water-soluble behavior. The copolymer did not show cytotoxicity against normal lung, skin fibroblasts, or nasal polyps fibroblasts. Through the present work, we also present the ability to control the properties of cross-linked hydrogels by altering copolymer’s composition and cross-linking parameters (curing temperature and time). Hydrogels were then studied in terms of water-uptake capacity for a period up to six days. The techniques Proton Nuclear Magnetic Resonance (1H NMR), Thermogravimetric Analysis (TGA), Size Exclusion Chromatography (SEC), and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR) were applied for the characterization of the synthesized copolymers and the cross-linked hydrogels. Three samples of biofertilizers based on collagen hydrolysate functionalized with P(SSNa-co-GMAx) and starch and having nutrients encapsulated (N, P, K) were prepared and characterized by physical–chemical analysis and Energy Dispersive X-ray analysis-Scanning Electron Microscope (EDAX-SEM) in terms of microstructure. Preliminary tests for application as fertilizers were performed including the release degree of oxidable organic compounds.


1948 ◽  
Vol 21 (2) ◽  
pp. 301-313 ◽  
Author(s):  
Geoffrey Gee

Abstract The tensile properties of a range of pure-gum natural rubbers have been reviewed, and it has been shown that their principal features can be understood on the assumption that the tensile strength measured in a given test depends directly on the amount of crystallization at break. The most important single factor in determining tensile strength is the degree of cross-linking. Cross-linking is only needed in order to prevent plastic flow, thus making it possible for the molecules to align themselves by stretching, and hence to crystallize. A very highly cross-linked rubber is weak because the load required to stretch it is so high that the rubber is broken before the elongation becomes large enough to produce crystallization. In general, vulcanization also involves reactions, e.g., the combination of sulfur with the rubber, which inhibit crystallization by producing structural modifications of the rubber. These reduce the tensile strength, especially when the degree of cross-linking is large. These ideas readily explain the effects of swelling and of the temperature of test. They are also used in a brief discussion of the phenomena of overcure, reversion, and aging.


2018 ◽  
Vol 789 ◽  
pp. 221-225
Author(s):  
Nattapol Dedruktip ◽  
Wasan Leelawanachai ◽  
Nuchnapa Tangboriboon

Alumina fiber is a ceramic material used as a dispersed phase or filler to reinforce the mechanical and improve thermal properties of natural rubber via vulcanization process at curing temperature 150°C. The amount of alumina fiber added in natural rubber was varied from 0 to 50 phr on 100 phr of natural rubber in a sulfur curing system. Adding 10 phr alumina fiber affects to obtain the best natural rubber composite samples having good mechanical and thermal properties. Tensile strength, elongation at break, Young’s modulus and thermal conductivity of adding 10 phr whisker alumina fiber encoded NR-Al-10 are equal to 14.38±1.95 MPa, 1038.4±41.45%, 545.63±25.67 MPa and 0.2376±0.0003 W/m.K, respectively, better than those of pure natural rubber compounds without adding alumina fiber. Tensile strength, elongation at break, Young’s modulus and thermal conductivity of natural rubber without adding alumina fiber are equal to 14.06±6.03 MPa, 949.41±52.15%, 496.32±8.54 MPa and 0.2500±0.0003 W/m.K, respectively.


2018 ◽  
Vol 51 (5) ◽  
pp. 406-420 ◽  
Author(s):  
Nuttida Srirachya ◽  
Takaomi Kobayashi ◽  
Kumarjyoti Roy ◽  
Kanoktip Boonkerd

In this article, thermoreversible covalent cross-linking of maleated natural rubber (MNR) with glycerol was studied. Firstly, NR was grafted with maleic anhydride using a reactive processing method. The result showed that MNR was successfully obtained without the addition of initiator. The highest grafting was 1.76%. Secondly, the obtained MNR was dissolved in toluene and then mixed with glycerol, which is used in this study as the thermoreversible cross-linking agent. Fourier transform infrared spectra of the casted MNR film mixed with glycerol showed that upon heating, covalent ester cross-links were formed via the reaction of succinic anhydride ring with hydroxyl groups of glycerol. The swelling test indicated that the swelling index (%) decreased with increasing glycerol loading. This indicated that the degree of cross-linking directly depended on the amount of glycerol. The tensile strength and modulus were significantly improved upon increasing the level of cross-linking. The MNR cross-linked with glycerol can be remolded at 150°C more than three times. After remolding, the mechanical properties decreased with increasing recycling round.


2020 ◽  
Vol 90 (17-18) ◽  
pp. 2097-2108
Author(s):  
Guizhen Ke ◽  
Zhiheng Xiao ◽  
Xinya Jin ◽  
Lixiang Yu ◽  
Jianqiang Li ◽  
...  

The formaldehyde-free crease-proof finishing agent 1,2,3,4,-butanetetracarboxylic acid (BTCA) was used to treat lyocell fabrics. The effects of BTCA concentration and curing temperature on the wrinkle recovery angle (WRA) and tensile breaking strength of lyocell fabrics were discussed. The results showed that with the increase of BTCA concentration and curing temperature, the WRA value of lyocell fabrics increased obviously and the maximum WRA reached 147°, but breaking strength decreased gradually and the minimum strength retention was 68%. The WRA was durable against laundering. The fabric whiteness difference was not obvious and the whiteness retention of all samples exceeded 98%. After further alkali treatment, the WRA of the treated lyocell fabrics decreased and the fracture strength retention recovered to varying degrees (0.45–10.8%). The developed regression equations were found to be in good correlation ( r2 > 92%) with the selected variables (tensile strength, BTCA concentration, curing temperature). Fourier transform infrared spectroscopy analysis confirmed that the tensile strength loss of BTCA-treated lyocell fabrics was caused by cross-linking of cellulose molecules and acid degradation. Tensile strength loss that resulted from ester bonding could be restored after hydrolysis in alkaline solution. The recoverable magnitude of tensile strength was related to the curing temperature. A high temperature not only promoted the cross-linking of cellulose macromolecules, but also accelerated the acid degradation of cellulose.


2020 ◽  
Vol 49 (1) ◽  
pp. 11-18
Author(s):  
Khaled Mostafa ◽  
Azza El-Sanabary

Purpose This study aims to explore the incorporation of the authors previously prepared chitosan nanoparticles (CNPs) of size around 60-100 nm in the cross-linking formulation of viscose fabrics to see CNPs impact in terms of imparting multi-functional characteristics such as tensile strength, dry wrinkle recovery angles and antibacterial properties. Design/methodology/approach CNPs of size around 60-100 nm were incorporated in cross-linking formulations for viscose fabrics, including different concentrations of glutaraldehyde as a non-formaldehyde cross-linking agent and magnesium chloride hexahydrate as a catalyst. The formulations were applied at different curing times and temperatures in 100 mL distilled water, giving rise to a wet pickup of ca. 85 per cent. The fabrics were dried for 3 min at 85°C and cured at specified temperatures for fixed time intervals in thermo fixing oven according to the traditional pad-dry-cure method. Findings The above eco-friendly method for finished viscose fabrics was found to obtain high dry wrinkle recovery angle and maintain the tensile strength of the finished fabric within the acceptable range, as well as antibacterial properties against Escherichia coli and Staphylococcus aureus as a gram-negative and gram-positive bacteria, respectively. Both, scanning electron microscope and nitrogen percent on the finished fabric confirm the penetration of CNPs inside the fabric structure. Finally, viscose fabrics pageant antibacterial activity against gram-positive and gram-negative bacteria assessed even after 20 washing cycle. Research limitations/implications CNPs with its flourishing effect with respect to cationic nature, biodegradability, reactivity, higher surface area and antimicrobial activity; in addition to glutaraldehyde as non-formaldehyde finishing agent can be used as multi-functional agents for viscose fabrics instead of DMDHEU, polyacrylate and monomeric composites as hazardous materials. Practical implications CNPs as cationic biopolymers were expected to impart multi-functional properties to viscose fabrics especially with obtaining reasonable dry wrinkle recovery angle and tensile strength in addition to antibacterial properties. Originality/value The novelty addressed here is undertaken with a view to impart easy care characteristics and antibacterial activities onto viscose fabrics using CNPs as antimicrobial agent and glutaraldehyde as non-formaldehyde durable press finishes to-replace the traditional formaldehyde-based resins. Besides, to the authors’ knowledge, there is no published work so far using the above cross-linking formulation written above.


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