بررسي تاثير افزودن رزين فنوليك بر چسبندگي آميزه لاستيك NBR به پارچه نايلون 6و6 و ارزيابي مقاومت پيرشدگي‌آن

One of the most challenging issues in the rubber industry is the aging behavior of materials under different environmental conditions. Nitrile rubber, also known as acrylonitrile-butadiene rubber (NBR), swells an‎d undergoes changes in its polymer network structure when in long-term contact with hydrocarbon oils an‎d fuels. This leads to a decrease in hardness an‎d tensile strength over time. Therefore, using reinforcing materials is necessary to mitigate the aging of nitrile rubber. Nylon 6,6, due to its desirable mechanical properties an‎d stability, is commonly used as a reinforcing layer in nitrile rubber compounds. However, the incompatibility between these two materials an‎d the lack of sufficient adhesion present significant industrial challenges. To address this, this study investigated the effect of alkyl resins (Volcador A) on the physical, mechanical, an‎d adhesion properties of NBR blends. Various formulations of nitrile rubber blends containing different amounts of resin were designed an‎d prepared through mixing in a Banbury mixer an‎d compression curing. The aim of this study was to enhance the interfacial interaction between the rubber matrix an‎d nylon 6,6 fibers, thereby improving the bond strength between these two phases. Several characterization tests, including FTIR, DSC, DMTA, rheometry, hardness, tensile strength, an‎d adhesion properties, were performed. The tensile strength an‎d elongation-to-rupture tests demonstrated that the presence of resin within the optimal range improved mechanical strength from 16.5 MPa to 17.3 MPa, without a significant reduction in the systemʹs flexibility. Additionally, adhesion test results indicated that the addition of Volcador A resin increased surface polarity, enhanced wettability, an‎d strengthened the bond between the rubber an‎d nylon fabric. Thermal studies using DSC revealed the curing characteristics an‎d indicated that the resin has a direct effect on the thermal stability of the mixture. FTIR spectroscopy analysis also showed the formation of new chemical an‎d physical interactions between the functional groups of the resin an‎d the nitrile chains in the NBR matrix. The sample containing 5 phr of resin was identified as the optimal sample among those studied, based on rheometric, mechanical, an‎d adhesion properties. This sample exhibited a 163% improvement in curing speed, along with a significant increase in shear time. Furthermore, the adhesion of this mixture to nylon 6,6 increased from 1.4 lbf/in to 1.14 lbf/in. The adhesion of the mixture after immersion in oil an‎d fuel was measured at 11.7 lbf/in an‎d 11.52 lbf/in, respectively, which shows desirable values compared to the reference sample before aging. The hardness of the optimal mixture also increased by approximately 5% after immersion in oil an‎d fuel compared to the reference sample. Ultimately, the results of this study show that using Volcador A resin as an additive in NBR compounds is an effective solution for simultaneously improving mechanical, thermal, an‎d adhesion properties in nylon fiber-reinforced rubber systems.

افسانه فخار

مهدي رزاقي كاشاني , محمود معصومي