Development of Liquid Diene Rubber Based Highly Deformable Interactive Fiber-Elastomer Composites

The preparation of intelligent structures for multiple smart applications such as soft-robotics, artificial limbs, etc., is a rapidly evolving research topic. In the present work, the preparation of a functional fabric, and its integration into a soft elastomeric matrix to develop an adaptive fiber-elastomer composite structure, is presented. Functional fabric, with the implementation of the shape memory effect, was combined with liquid polybutadiene rubber by means of a low-temperature vulcanization process. A detailed investigation on the crosslinking behavior of liquid polybutadiene rubber was performed to develop a rubber formulation that is capable of crosslinking liquid rubber at 75 °C, a temperature that is much lower than the phase transformation temperature of SMA wires (90–110 °C). By utilizing the unique low-temperature crosslinking protocol for liquid polybutadiene rubber, soft intelligent structures containing functional fabric were developed. The adaptive structures were successfully activated by Joule heating. The deformation behavior of the smart structures was experimentally demonstrated by reaching a 120 mm bending distance at an activation voltage of 8 V without an additional load, whereas 90 mm, 70 mm, 65 mm, 57 mm bending distances were achieved with attached weights of 5 g, 10 g, 20 g, 30 g, respectively.

NUMERICAL ANALYSIS OF HEAT TRANSFER AND CHEMICAL REACTION COUPLING IN THE RUBBER SEAL VULCANIZATION PROCESS

ABSTRACT Vulcanization parameters significantly affect the performance of rubber seals and the energy savings of the manufacturing process, which require a relationship between process parameters and vulcanization characteristics. Based on the vulcanization kinetics of rubber seal materials, a transient thermochemical-coupled finite-element model of the vulcanization process was established and solved. Changes in thermal conductivity and specific heat capacity during vulcanization were considered in detail. The effects of operational and structural parameters, such as mold temperature, heating duration, and rubber seal shape, cross-sectional dimensions on vulcanization characteristics were investigated. Finally, feasible suggestions for the vulcanization production of rubber seals are discussed. The study is expected to design parameters and control the vulcanization process of rubber seals accurately.

Effect of Vulcanization Process Parameters on the Tensile Strength of Carcass of Textile-Rubber Reinforced Conveyor Belts

Textile-reinforced conveyor belts are most widely used in various industries, including in the mining, construction, and manufacturing industries, to transport materials from one place to another. The conveyor belt’s tensile strength, which primarily relies on the property of the carcass, determines the area of application of the belt. The main aim of the current work was to investigate the influence of vulcanization temperature and duration of the vulcanization process on the tensile properties of the carcass part of the conveyor belt. An extensive experiment was carried out on the tensile properties of woven fabrics that were intended to reinforce conveyor belts by aging the fabrics at the temperature of 140 °C, 160 °C, and 220 °C for six and thirty-five minutes of aging durations. Afterward, the textile-reinforced conveyor belts were produced at vulcanization temperatures of 140 °C, 160 °C, and 220 °C for six and thirty-five minutes of vulcanizing durations. The influence of the vulcanization process parameters on the tensile property of fabrics utilized for the reinforcement of the conveyor belt was analyzed. In addition, the effect of the dipping process of woven fabric in resorcinol–formaldehyde–latex on the tensile property of polyester/polyamide 66 woven fabric (EP fabric) was investigated. The investigation results revealed that the tensile strength of the carcass of the conveyor belt was significantly affected by vulcanization temperature. The conveyor belt vulcanized at 160 °C for 35 min has shown the optimum tensile strength, which is 2.22% and 89.06% higher than the samples vulcanized at 140 °C and 220 °C for 35 min, respectively. Furthermore, the tensile strength and percentage elongation at break of conveyor belts vulcanized at 220 °C were almost destroyed regardless of the vulcanization duration.

Enhancement of thermoelectric and mechanical properties of thermoplastic vulcanizates (TPVs) with hydroxylated graphene by dynamic vulcanization

In order to obtain higher thermoelectric and mechanical properties in nonpolar thermoplastic vulcanizates (TPVs), the butyl rubber/polypropylene (TPVs)/hydroxylated graphene (HGE) composites with nanosheet network were prepared through masterbatch technique and based on thermodynamic calculations, using polypropylene-graft-maleic anhydride (PP-MA) as a compatibilizer. The Fourier transform infrared (FTIR) and Raman spectra revealed the introduced maleic anhydride group on PP-MA can form strong interfacial interaction with hydroxyl-containing functional groups on HGE. Morphology study indicated the rubber particles in the composites occupied the most volume of the PP phase, as expected to hinder the aggregation of HGE and form the effective nanosheet network. The nanosheet network can be combined with the butyl rubber (IIR) cross-linked particles during the dynamic vulcanization process to improve the interface bonding between PP and IIR, thus increasing the tensile strength of TPVs. The prepared TPVs/HGE composites have significantly improved in mechanical properties, thermal properties and dielectric properties, which provides a guarantee for their potential application as multifunctional TPVs polymers.

Preparation of polyoxymethylene/methyl vinyl silicone rubber/thermoplastic polyurethane ternary thermoplastics vulcanizates with good toughness properties

Novel thermoplastic vulcanizates (TPVs) based on polyoxymethylene (POM) and methyl vinyl silicone rubber (MVQ) have been prepared by dynamic vulcanization process through a batch mixer. During the preparation of TPV blends, Di-(tert butyl peroxyisopropyl) benzene (BIBP) was used as the curing agent in order to make MVQ cross-linked and TPU was used to coat MVQ for improving the compatibility of MVQ and POM. In order to understand the influence of different compositions on TPV blends, five groups of experimental processes were described in detail. During these experiments, the amount of POM was reduced from 70phr to 30phr, that of MVQ was gradually increased from 18phr to 42 phr, and TPU was increased from 12phr to 28phr. In addition, the morphology and properties of TPVs were studied by DSC, FTIR, SEM, DMA and mechanical tests. The mechanical testing results showed that with the amount of POM decreasing and the total amount of MVQ and TPU increasing, the tensile strength of the TPV blends gradually was decreased, and the elongation at break was increased accordingly from 35.2 ± 6% of pure POM to 142.8 ± 11% of sample 5#.

Vulcanization of Elastomers with Quinol Ethers of P-Benzoquinone Dioxime

The article discusses the synthesis and development of the direction of vulcanization of elastomers with quinol esters of p-benzoquinone dioxime. The concept of a critical temperature Tcr which denotes noticeability of the vulcanization process of unsaturated rubbers (with k=1×10-6, s-1) is introduced. Noted the increased vulcanizational activity of quinol esters of p-quinone dioxime after nitrosoarenes addition. The reactional ability of nitrosoarenes is proportional to estimated charge value on the oxygen of the nitroso group, with lgk= 11,3+49,7 qO. Quinol esters of p-quinone dioxime are proposed to create three-dimensional rubber paintings and prints.

Influence of Phytonorman Eco-Oils Nature and Content on Processing of the Elastomeric Materials Based on Nitrile Butadiene Rubber Analysis

The work presents the results of testing new eco-oils in elastomeric materials based on nitrile butadiene rubber (NBR). The influence of eco-oils grade and content on the rubber mixes based on NBR 2665 processing was studied. It is established that Phytonorman 212 acts as a technologically active additive that improves the rheological and relaxation characteristics of rubber mixes. Phytonorman 213 acts as an activator of the vulcanization process when eco-oils content is 2 phr. To maintain the complex of physical, mechanical and working performances, so as to prevent the slowdown of the vulcanization process at 7 phr eco-oil content it is recommended to adjust vulcanizing group component content and filler grade.