Natural rubber/tetra-needle-like zinc oxide whisker composites: their preparation and characterization

2018 ◽  
Vol 38 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Xi Chen ◽  
Zhibiao Hu ◽  
Fuquan Zhang ◽  
Zhusen Zhang
Keyword(s):  
Mechanical Properties ◽  
Zinc Oxide ◽  
Natural Rubber ◽  
Dimensional Structure ◽  
Rubber Matrix ◽  
Cross Link ◽  
Link Density ◽  
Oxide Whisker ◽  
Cross Link Density ◽  
Latex Compounding

Abstract Tetra-needle-like zinc oxide whiskers (T-ZnOw) were modified by Si69, and natural rubber (NR)/Si69-T-ZnOw composites were developed by latex-compounding techniques. The mechanical properties, morphology, cross-link density, and thermogravimetry of the composites were investigated. The results show that the tetra-needles of T-ZnOw tightly insert into the rubber matrix. T-ZnOw, which have a special four-dimensional structure, act as a skeleton in the rubber matrix. In comparison with the host NR, the mechanical properties, cross-link density, and thermostability of the resulting composites were significantly improved at Si69-T-ZnOw loadings of 4 wt%. During the thermal decomposition, various characteristic temperatures of the NR/Si69-T-ZnOw composites increase 5–9°C over those of the pure NR. The NR/Si69-T-ZnOw composites have great potential to manufacture medical protective products with high performances.

REINFORCED MECHANICAL PROPERTIES OF FUNCTIONALIZED SILICA AND EGGSHELL FILLED GUAYULE NATURAL RUBBER COMPOSITES

2019 ◽  
Vol 92 (4) ◽  
pp. 687-708 ◽  
Author(s):  
Xianjie Ren ◽  
Yang Geng ◽  
Alfred B. O. Soboyejo ◽  
Katrina Cornish
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Energy Consumption ◽  
Natural Rubber ◽  
High Surface ◽  
Particle Diameter ◽  
Cross Link ◽  
Final Particle ◽  
Link Density ◽  
Cross Link Density

ABSTRACT Replacing synthetic fillers, which are commonly used to reinforce rubber, with bio-fillers has potential to improve the sustainability of rubber products. Eggshell (ES) (a powder with a maximum particle diameter of 9.4 μm and a median of 1.1 μm) was added to guayule natural rubber (GNR) composites to partially or fully replace bifunctionally silanized, high surface area, precipitated silica (BSS). The mixing energy consumption, mechanical properties, cross-link density, filler dispersion and final particle size, fracture surface morphology, and dyeability of GNR composites were characterized. ES filler effectively reinforced vulcanized GNR compared with unfilled vulcanized GNR. Energy consumption, modulus at 300% strain (M300), and hardness generally decreased with increasing ES fraction (decreasing BSS), but tensile strength, gel fraction, and elongation at break increased even where cross-link density and M300 were similar. Thus, composite cross-link density was not solely influenced by silane content as the ratio and loading of ES and BSS changed. The production of the composites reduced particle size to submicron size. Even a small amount of ES improved the dispersion of BSS filler particles in the composites and hence the mechanical properties. The contributions of the two fillers to the composite properties are explained. Linear mixed models were built to predict the mechanical properties of a broader range of GNR–ES–BSS composites, and r2 (the quality of the model predictability) was above 0.9 for all models. ES filled GNR, with or without BSS, can be dyed different colors for specific applications. The lower-cost, renewability, dyeability, and excellent performance of ES–GNR composites addresses the need for sustainable rubber products with low carbon footprint.

PRECIPITATED NANO ZINC HYDROXIDE ON THE SILICA SURFACE AS AN ALTERNATIVE CURE ACTIVATOR IN THE VULCANIZATION OF NATURAL RUBBER

2017 ◽  
Vol 90 (4) ◽  
pp. 714-727 ◽  
Author(s):  
Md. Najib Alam ◽  
Pranut Potiyaraj
Keyword(s):  
Zinc Oxide ◽  
Natural Rubber ◽  
Precipitation Method ◽  
Zinc Hydroxide ◽  
Mechanical And Thermal Properties ◽  
Cross Link ◽  
Rubber Vulcanizate ◽  
Link Density ◽  
Cross Link Density ◽  
Cure Activator

ABSTRACT We synthesized precipitated zinc hydroxide on the surface of precipitated silica via a conventional precipitation method. The zinc hydroxide is characterized by Fourier transform infrared spectroscope, X-ray diffraction, and field-emission scanning electron microscope measurements. The synthesized zinc hydroxide is a platelike structure with an average nano dimension of 40 nm in crystalline depth. The aim of the present study is to reduce the cure activator level of conventional environment pollutant zinc oxide in the vulcanization of natural rubber. To study the effects of the synthesized zinc hydroxide on the vulcanization of natural rubber curing, mechanical and thermal properties were determined and compared with the vulcanized properties of conventional 5 phr (per hundred grams of rubber) zinc oxide cured rubber vulcanizate. A strong enhancement in the cross-link density and mechanical properties (namely, modulus, tensile strength, and hardness) with only 2 phr of synthesized zinc hydroxide cured rubber system compared with 5 phr of conventional zinc oxide cured rubber system was found. A slightly higher thermal stability of 2 phr zinc hydroxide cured vulcanizate was observed because of better cross-link density than conventional 5 phr zinc oxide cured rubber vulcanizate. Thus, by this novel method, a greater than 60% reduction of the conventional cure activator level can be possible with improved physical properties in the vulcanization of natural rubber.

Boron nitride for modification of rubber based on isoprene elastomer

2020 ◽  
pp. 105-112
Author(s):  
K. S. Zhansakova ◽  
E. N. Eremin ◽  
G. S. Russkikh ◽  
O. V. Kropotin
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Gradual Increase ◽  
Physical And Mechanical Properties ◽  
Curing Time ◽  
Cross Link ◽  
Start Time ◽  
Link Density ◽  
Cross Link Density ◽  
Isoprene Rubber

The work studies vulcanization characteristics of elastomers based on isoprene rubber filled with carbon black N330 and boron nitride (BN). The influence of the boron nitride (BN) concentration on technological, dynamic, physical and mechanical properties of elastomers has been researched. The application of boron nitride for producing rubber with good properties has been considered. With a gradual increase of the inert filler BN concentration up to 35%, a decrease in the curing rate by 33% and polymer cross-link density by 26% is observed. Moreover, the start time of vulcanization increases by almost 300%, the optimal curing time by 200%.

scholarly journals Magnetic composites based on NR and strontium ferrite

2019 ◽  
Vol 12 (1) ◽  
pp. 63-69
Author(s):  
Ján Kruželák ◽  
Andrea Kvasničáková ◽  
Rastislav Dosoudil ◽  
Ivan Hudec
Keyword(s):  
Carbon Black ◽  
Strontium Ferrite ◽  
Rubber Matrix ◽  
Cross Link ◽  
Magnetic Composites ◽  
Link Density ◽  
Cross Links ◽  
Cross Link Density ◽  
The Cross ◽  
Thermo Physical Properties

Abstract Two types of composites based on natural rubber (NR) and strontium ferrite were tested in this study. Composites of the first type were prepared by incorporation of strontium ferrite in the concentration range ranging from 0 to 100 phr (parts per hundred rubber) into pure NR based rubber matrix, while with those of the second type, strontium ferrite was dosed in the same concentration level into NR based rubber batch with constant amount of carbon black — 25 phr. For rubber matrices cross-linking, a standard sulfur based curing system was used. This work is focused on the effect of magnetic filler content on physico-mechanical, magnetic and thermo-physical properties of composite materials. Subsequently, the cross-link density and the structure of the formed sulfidic cross-links were examined. The results showed that the cross-link density of both types of composites increased with the increasing content of magnetic filler, while the structure of the sulfidic cross-links was almost not influenced by the amount of strontium ferrite. Tensile strength of rubber composites with pure rubber matrix was slightly improved by the incorporation of ferrite, while in case of composites based on a carbon black batch, the incorporation of magnetic filler resulted in the decrease of this characteristic. The presence of magnetic filler in both types of composites leads to a significant increase of the remanent magnetic induction.

PEG Cross-Linked Alginate Hydrogels with Controlled Mechanical Properties

1998 ◽  
Vol 530 ◽  
Author(s):  
Petra Eiselt ◽  
Jon A. Rowley ◽  
David J. Mooney
Keyword(s):  
Mechanical Properties ◽  
Tissue Engineering ◽  
Molecular Weight ◽  
Elastic Modulus ◽  
Cell Transplantation ◽  
Cross Linking ◽  
Cross Link ◽  
Link Density ◽  
A Cell ◽  
Cross Link Density

AbstractReconstruction of tissues and organs utilizing cell transplantation offers an attractive approach for the treatment of patients suffering from organ failure or loss. Highly porous synthetic materials are often used to mimic the function of the extracellular matrix (ECM) in tissue engineering, and serve as a cell delivery vehicle for the formation of tissues in vivo. Alginate, a linear copolysaccharide composed of D-mannuronic acid (M) and L-guluronic acid (G) units is widely used as a cell transplantation matrix. Alginate is considered to be biocompatible, and hydrogels are formed in the presence of divalent cations such as Ca2+, Ba2+ and Sr2+. However, ionically cross-linked alginate gels continuously lose their mechanical properties over time with uncontrollable degradation behavior. We have modified alginate via covalent coupling of cross-linking molecules to expand and stabilize the mechanical property ranges of these gels. Several diamino PEG molecules of varying molecular weight (200, 400, 1000, 3400) were synthesized utilizing carbodiimide chemistry. Sodium alginate was covalently cross-linked with these cross-linking molecules, and mechanical properties of the resulting hydrogels were determined. The elastic modulus of the cross-linked alginates depended on the molecular weight of the cross-linking molecules, and ranged from 10-110 kPa. The theoretical cross-link density in the hydrogels was also varied from 3 to 47% (relative to the carboxylic groups in the alginate) and the mechanical properties were measured. The elastic modulus increased gradually and reached a maximum at a cross-link density of 15%. In summary, covalently coupled hydrogels can be synthesized which exhibit a wide range of mechanical properties, and these materials may be useful in a number of tissue engineering applications.

scholarly journals Application of Peroxide Curing Systems in Cross-Linking of Rubber Magnets Based on NBR and Barium Ferrite

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Ján Kruželák ◽  
Andrea Kvasničáková ◽  
Elena Medlenová ◽  
Rastislav Dosoudil ◽  
Ivan Hudec
Keyword(s):  
Mechanical Properties ◽  
Barium Ferrite ◽  
Cross Linking ◽  
Butadiene Rubber ◽  
Cross Link ◽  
System Composition ◽  
Peroxide Curing ◽  
Link Density ◽  
Cross Link Density ◽  
Curing Systems

Rubber magnetic composites were prepared by incorporation of barium ferrite in constant amount—50 phr into acrylonitrile-butadiene rubber. Dicumyl peroxide as the curing agent was used for cross-linking of rubber magnets alone, or in combination with four different types of co-agents. The main aim was to examine the influence of curing system composition on magnetic and physical-mechanical properties of composites. The cross-link density and the structure of the formed cross-links were investigated too. The results demonstrated that the type and amount of the co-agent had significant influence on cross-link density, which was reflected in typical change of physical-mechanical properties. The tensile strength increased with increasing amount of co-agents, which can be attributed to the improvement of adhesion and compatibility on the interphase filler-rubber due to the presence of co-agents. Magnetic characteristics were found not to be influenced by the curing system composition. The application of peroxide curing systems consisting of organic peroxide and co-agents leads to the preparation of rubber magnets with not only good magnetic properties but also with improved physical-mechanical properties, which could broaden the sphere of their application uses.

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