Effect of High-Dispersed Nano-ZnO on the Properties of Vulcanized Natural Rubber

High-dispersed nano-ZnO were used for alternating ordinary ZnO in the vulcanization process of nature rubber. The properties of vulcanized natural rubber including the mechanical properties and anti-aging properties were investigated in this paper. The results showed that high-dispersed nano-ZnO made natural rubber the scorched time longer, the degrees of cross-linking higher and anti-aging properties remarkably stronger, compared with 99.5 % of ordinary ZnO under the same vulcanization conditions. Specially, when 0.8 dosages of high-dispersed nano-ZnO being used, the mechanical properties and anti-aging ability of natural rubber were best and better than that of 5 dosages of 99.5 % of ordinary ZnO in traditional formula. The reasons may be that high-dispersed nano-ZnO were completely resolved in rubber and can fully be contacted with the double bond of rubber molecules and the surface of sulfur so that they increased the efficiency of rubber vulcanization to improve the properties of natural rubber.

Radical Mechanisms in Saturated and Olefinic Systems. II. Disubstitutive Carbon-Carbon Cross-Linking by Tertiary Alkoxy Radicals in Isoprenic Olefins and Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3543108 ◽

1951 ◽

Vol 24 (4) ◽

pp. 777-786

Author(s):

E. H. Farmer ◽

C. G. Moore

Keyword(s):

Natural Rubber ◽

Cross Linking ◽

Chain Molecules ◽

Alkoxy Radicals ◽

Full Extent ◽

Carbon Chains ◽

Butyl Peroxide ◽

High Degree ◽

Vulcanization Process

Abstract The high degree of dehydrogenation effected by tert.-butoxy radicals at the α-methylenic groups of olefins enables these radicals to be used for the carbon-to-carbon cross-linking of unsaturated carbon chains, and especially of the polyisoprenic chains of natural rubber. Such cross-linking amounts to a vulcanization process in which the connecting links between chain molecules are just C—C bonds, which may be expected to have appropriate attributes. An examination has first been made of the cross-linking produced by tert.- butoxy radicals (from di-tert.-butyl peroxide) at 140° between the short iso-prenic chains in 1-methylcyclohexene, 4-methylhept-3-ene, 2,6-dimethylocta-2, 6-diene, and digeranyl. Cross-linking proceeds efficiently in each case, and the points of union in these isoprene units which become directly joined are not confined to original α-methylenic carbon atoms. Where the reagent radicals are in considerable deficit, e.g., one per two or three of the isoprene units present, those olefin molecules which are attacked become linked together mostly by single unions to form aggregates containing two, three or four molecules; but in the tetraisoprenic olefins the extent to which more than one union is formed between some of the directly linked molecules becomes appreciable. In natural rubber, cross-linking occurs smoothly and to nearly the full extent corresponding to the (in practice restricted) proportion of peroxidic reagent employed. Good vulcanizates can be so obtained in which the tensile stength is found to increase towards a maximum and then to decline rapidly as the degree of cross-linking steadily increases. Thus to obtain vulcanizates of the optimum physical characteristics, the degree of cross-linking must be suitably chosen. The role of the peroxidic reagent is almost entirely non-additive and non-degradative.

Influences of Particle Sizes on Properties of Natural Rubber/Waste Ground Rubber Powders Blends

10.4028/www.scientific.net/amr.773.668 ◽

2013 ◽

Vol 773 ◽

pp. 668-672

Author(s):

Jun Liang Liu ◽

Ping Liu ◽

Xiao Qiang Tang ◽

Dong Zeng ◽

Xing Kai Zhang ◽

...

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Natural Rubber ◽

Chemical Activation ◽

Cross Linking ◽

Particle Sizes ◽

Elongation At Break ◽

Tear Strength ◽

Rubber Waste ◽

Ground Rubber

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.

Characterization of the Reversion Process in Accelerated Sulfur Curing of Natural Rubber

Rubber Chemistry and Technology ◽

10.5254/1.3535831 ◽

1981 ◽

Vol 54 (4) ◽

pp. 734-750 ◽

Cited By ~ 36

Author(s):

C. H. Chen ◽

J. L. Koenig ◽

J. R. Shelton ◽

E. A. Collins

Keyword(s):

Mechanical Properties ◽

Natural Rubber ◽

Structural Basis ◽

Rubber Vulcanizate ◽

Chemically Induced ◽

Vulcanization Process ◽

Sulfur Curing

Abstract From studies of a series of accelerated sulfur vulcanizations of natural rubber, the structural basis of the reversion in macroscopic physical-mechanical properties has been determined. The amount of chemically induced trans-methine butadiene-like structure increases as the reversion process proceeds. When there is no observable reversion, there is no detectable trans-methine butadiene-like structure. The presence of the trans-methine butadiene-like structure is detrimental to the properties of the natural rubber vulcanizate. The vulcanization process involves two competing processes, namely, crosslinking and desulfuration. The latter process produces the trans-methine structure which is responsible for the reversion in properties.

Preparation and Properties of LLDPE/EVA/Nano-ZnO Composites

10.4028/www.scientific.net/amr.183-185.1864 ◽

2011 ◽

Vol 183-185 ◽

pp. 1864-1868

Author(s):

Jia Liu ◽

Shu Sheng Jia

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Process Parameters ◽

Orthogonal Experiment ◽

Optimization Method ◽

Step Method ◽

Swarm Optimization ◽

Nano Zno ◽

Fracture Elongation ◽

The process parameters of LLDPE/EVA/nano-ZnO composites were optimized by two methods. Samples were prepared under the better process parameters. The dispersion morphology and the mechanical properties of material were studied by Field Emission Scanning Electron Microscope (FESEM). And the mechanical properties of LLDPE/EVA/nano-ZnO composites were tested. It was showed that the optimization method based on neural network of BP and particle swarm optimization was better than that optimization method based on orthogonal experiment. The nanoeffect of ZnO particles was exerted which were distributed in LLDPE/EVA matrix, which result in the effect of reinforcing and toughening. Two-step method was better than direct dispersing method. The tensile strength was the highest when nano-ZnO amount was 3% under the two-step, the tensile strength was increased up to about 22%, and the fracture elongation rate was increased up to about 11%.

Thermoreversible cross-linking of maleated natural rubber with glycerol

Journal of Elastomers & Plastics ◽

10.1177/0095244318790616 ◽

2018 ◽

Vol 51 (5) ◽

pp. 406-420 ◽

Cited By ~ 1

Author(s):

Nuttida Srirachya ◽

Takaomi Kobayashi ◽

Kumarjyoti Roy ◽

Kanoktip Boonkerd

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Natural Rubber ◽

Succinic Anhydride ◽

Processing Method ◽

Cross Linking ◽

Hydroxyl Groups ◽

Reactive Processing ◽

Cross Links ◽

Maleated Natural Rubber

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.

Enhancement the Thermal Stability and the Mechanical Properties of Acrylonitrile-Butadiene Copolymer by Grafting Antioxidant

International Journal of Polymer Science ◽

10.1155/2010/981690 ◽

2010 ◽

Vol 2010 ◽

pp. 1-7 ◽

Cited By ~ 2

Author(s):

Abdulaziz Ibrahim Al-Ghonamy ◽

A. A. El-Wakil ◽

M. Ramadan

Keyword(s):

Mechanical Properties ◽

Thermal Stability ◽

Natural Rubber ◽

Ultrasonic Attenuation ◽

Environmental Issues ◽

Life Time ◽

Roll Mill ◽

Grafting Copolymerization ◽

And Control ◽

Monomeric antioxidants are widely used as effective antioxidants to protect polymers against thermal oxidation. Low molecular weight antioxidants are easily lost from polymer through migration, evaporation, and extraction. Physical loss of antioxidants is considered to be major concern in the environmental issues and safety regulation as well as long life time of polymers. The grafting copolymerization of natural rubber ando-aminophenol was carried out by using two-roll mill machine. The prepared natural rubber-graft-o-Aminophenol, NR-graft-o-AP, was analysed by using Infrared and1-NMR Spectroscopy techniques. The thermal stability, mechanical properties, and ultrasonic attenuation coefficient were evaluated for NBR vulcanizates containing the commercial antioxidant, N-phenyl--naphthylamine (PBN), the prepared grafted antioxidant, NR-graft-o-AP, and the control vulcanizate. Results of the thermal stability showed that the prepared NR-graft-o-AP can protect NBR vulcanizate against thermal treatment much better than the commercial antioxidant, PBN, and control mix, respectively. The prepared grafted antioxidant improves the mechanical properties of NBR vulcanizate.

The Mechanical and Aging Properties of the Natural Rubber/Polyvinyl Alcohol (NR/PVA) Blends

10.4028/www.scientific.net/amr.1073-1076.12 ◽

2014 ◽

Vol 1073-1076 ◽

pp. 12-15 ◽

Cited By ~ 1

Author(s):

Ke Chen ◽

Rui Wang

Keyword(s):

Mechanical Properties ◽

Tensile Strength ◽

Polyvinyl Alcohol ◽

Natural Rubber ◽

Thermal Oxidation ◽

Material Properties ◽

Mechanical Test ◽

Aging Test ◽

Aging Properties ◽

Latex Compounding

The natural rubber/polyvinyl alcohol (NR/PVA) blends containing epoxid natural rubber as the compatilizer were prepared using latex compounding techniques. The mechanical and thermal oxidation aging properties were studied. Mechanical test showed that the tear strength and hardness of the NR were significantly improved due to adding of the PVA. The tensile strength decreased significantly along with the PVA increasing. Thermal oxidation aging test had obviously impact on the mechanical properties of the material. The performance retention of the material properties was taken effect significantly on the aging test.

Properties of Thermoplastic Natural Rubber (TPNR): Influence of Polypropylene Grades on TPNR Properties

10.4028/www.scientific.net/amr.844.127 ◽

2013 ◽

Vol 844 ◽

pp. 127-130 ◽

Cited By ~ 2

Author(s):

Chanida Manleh ◽

Charoen Nakason ◽

Natinee Lopattananon ◽

Azizon Kaesaman

Keyword(s):

Mechanical Properties ◽

Natural Rubber ◽

Crosslink Density ◽

Rubber Particle ◽

Complex Viscosity ◽

Morphological Properties ◽

Dynamic Vulcanization ◽

Thermoplastic Natural Rubber ◽

Pp Blends ◽

Vulcanization Process

Thermoplastic vulcanizate (TPV) based on natural rubber (NR) and polypropylene (PP) blends were successfully prepared through a dynamic vulcanization process using Brabender Plastograph EC Plus with a rotor speed of 60 rpm at 180°C. Sulfur vulcanization system was used to cure rubber phase in the TPVs. Three grades of PP (i.e., PP700J, HP553R and HP544T) were used to blend with NR at a fixed blend ratio of NR/PP = 60/40. The mechanical properties, crosslink density, complex viscosity and morphological properties of the blends were examined. The results revealed that the dynamically cured NR/PP700J samples showed the best mechanical properties because of higher crosslink density and smaller rubber particle size when compared with those of the blends combined with HP553R and HP544T. Furthermore, the complex viscosity of the TPVs was highest for the blends with PP700J.

Effect of Radiation-Induced Cross-Linking on Thermal Aging Properties of Ethylene-Tetrafluoroethylene for Aircraft Cable Materials

Materials ◽

10.3390/ma14020257 ◽

2021 ◽

Vol 14 (2) ◽

pp. 257

Author(s):

Xiaodong Zhang ◽

Fei Chen ◽

Zhimin Su ◽

Taiping Xie

Keyword(s):

Mechanical Properties ◽

Electron Beam ◽

Thermo Gravimetric Analysis ◽

Thermal Characteristics ◽

Volume Resistivity ◽

Cross Linking ◽

Gravimetric Analysis ◽

Aging Properties ◽

Radiation Induced ◽

Ethylene Tetrafluoroethylene

The effects of electron beam irradiation on ethylene-tetrafluoroethylene copolymer (ETFE) were studied. Samples were irradiated in air at room temperature by a universal electron beam accelerator for various doses. The effect of irradiation on samples and the cross-linked ETFE after aging were investigated with respect to thermal characteristics, crystallinity, mechanical properties, and volume resistivity using thermo-gravimetric analysis (TGA), differential scanning calorimeter (DSC), universal mechanical tester, and high resistance meter. TGA showed that thermal stability of irradiated ETFE is considerably lower than that of unirradiated ETFE. DSC indicates that crystallinity is altered greatly by cross-link. The analysis of mechanical properties, fracture surface morphology, visco-elastic properties and volume resistivity certify radiation-induced cross-linking is vital to aging properties.

Performance of multilayered LDPE films used as greenhouse cover in semiarid climate

Journal of Elastomers & Plastics ◽

10.1177/0095244318781963 ◽

2018 ◽

Vol 51 (3) ◽

pp. 211-223

Author(s):

M Aouinet ◽

K Djakhdane ◽

A Dehbi ◽

D Castronuovo ◽

P Picuno

Keyword(s):

Mechanical Properties ◽

Climatic Conditions ◽

Low Density Polyethylene ◽

Cross Linking ◽

Creep Recovery ◽

Low Density ◽

Monolayer Film ◽

Polyethylene Films ◽

Anisotropic Character ◽

The low-density polyethylene films used for greenhouse roof were naturally weathered for 9 months in harsh climatic conditions (Tiaret region, Algeria). The changes in the mechanical properties have been measured by tensile and creep-recovery tests. The measurements were carried out for both monolayer and tri-layer films. The anisotropic character of the films is preserved during ageing. The improvement in the creep resistance via cross-linking for both monolayer and tri-layer films affects different deformations. The results revealed that the degradation performance of these new tri-layer films is found to be quite better than that of the monolayer film, with regard to the mechanical properties.