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Additives
Published in Charles E. Carraher, Carraher's Polymer Chemistry, 2017
Captax (15.22) is used to the extent of 1% with hevea rubber and accounts for the major part of the over 30,000 tons of accelerators used annually in the United States. Other accelerators widely used include 2-mercaptobenzothiazole sulfonamide (Santocure; 15.23), used for the vulcanization of SBR; dithiocarbamates and thiuram disulfides. Thiuram disulfide (15.24) is a member of a group called ultra-accelerators that allow the curing of rubber at moderate temperatures and may be used in the absence of sulfur.
Industrial Polymers
Published in Manas Chanda, Plastics Technology Handbook, 2017
Thiokols are amorphous polymers which do not crystallize when stretched and hence reinforcing fillers, such as carbon black, must be added to obtain relatively high tensile strengths. Thiokol may be vulcanized in the presence of zinc oxide and thiuram accelerators, such as tetramethyl-thiuram disulfide (Tuads). The accelerators modify the sulfur links and serve as chemical plasticizers.
Evaluation of elastomer–plastomer vulcanised modifiers for using as bitumen binder modifier
Published in International Journal of Pavement Engineering, 2022
Mahmoudreza Favakeh, Saeed Bazgir, Morteza Karbasi, Mohammad Zia Alavi, Ali Abdi
The EPVs used contain three types of polymers: (1) linear low-density polyethylene (LLDPE), (2) styrene-butadiene rubber (SBR), (3) maleic anhydride grafted polyethylene (PE-g-MA) as a compatibiliser (or coupling agent). Table 1 shows the general properties of these polymers. The LLDPE was produced by Amir Kabir Petrochemical Company, Iran. The SBR was produced by Bandar Imam Petrochemical Company, Iran; and the compatibiliser was from KERANGIN Company. The EPVs also included Cloisite 15A nanoclay, with properties shown in Table 2, and a combination of vulcanising agents: sulphur, stearic acid, zinc oxide (ZnO), Mercapto-benzo-thiazole (MBTS) and tetra-methyl-thiuram disulfide (TMTD). All vulcanising materials were from Bayer Company. The method of production of EPVs is briefly explained below. A bitumen binder with 60/70 penetration grade, produced by Jey Oil Refining, Isfahan, was used in the production of EPVs and also as the base bitumen in the EPV-modified binders. General properties of the 60/70 bitumen are illustrated in Table 3.
Investigate the effect of ground tyre rubber as a reinforcement filler in natural rubber hybrid composites
Published in Soft Materials, 2023
P. Kaliyappan, M. Dhananchezian
Honorato et al.[14] reported that the NR was mixed with various types of accelerators. Accelerators are essential in controlling the cross-link performance of composites during curing processes. To enhance its mechanical properties, NR is blended with various accelerator combinations (Tetra Methyl Thiuram Disulfide (TMTD), Mercaptobenzothiazole (MBT), and Sulfads). It was reported that the formulation of NR vulcanized with MBT/TMTD offered excellent mechanical properties over other combinations.
Diphenolic acid-modified PAMAM/chlorinated butyl rubber nanocomposites with superior mechanical, damping, and self-healing properties
Published in Science and Technology of Advanced Materials, 2021
Yao Lu, Jincheng Wang, Le Wang, Shiqiang Song
The internal morphology and composition of CIIR/G2 PAMAM-H nanocomposites were further studied by SEM and energy-dispersive spectroscopy (EDS). As shown in Figure 4a-c, elements Cl, N and O were detected, which provided specific distribution information of elements within the materials. After adding G2 PAMAM, the distribution of N and O elements became uneven (Figure 4b3,b4). This was because the G2 PAMAM molecular structure contained many N and O elements, and G2 PAMAM tended to form large agglomerate. It was observed that the O elements of the nanocomposites were not uniformly distributed after addition of G2 PAMAM-H (Figure 4c3,c4). The uniform distribution of nitrogen was due to the reduction of the N content of the G2 PAMAM-H obtained after diphenolic acid replaced the end groups of G2 PAMAM. In addition, there was also a small amount of N element in the rubber additives (dibenzothiazole disulfide, tetramethyl thiuram disulfide), resulting in inconsistent distribution of nitrogen and oxygen. The large number of amides and hydroxyl groups contained in G2 PAMAM-H may lead to an increase in the content of O elements in the nanocomposites (Figure 4f). However, there was no significant difference in the distribution of the Cl element between pure CIIR and nanocomposites (Figure 4a2,b2,c2), indicating that the addition of G2 PAMAM andG2 PAMAM-H did not affect the uniformity of the system. The inner cavity of dendrimers was entangled with the molecular chains of rubber, which cannot destroy the integrity of CIIR. Comparing the infrared spectra of pure CIIR, CIIR/5 phr G2 PAMAM and CIIR/5 phr G2 PAMAM-H (Figure 4g), there was no obvious change in the Cl peak, which proved that the Cl in CIIR cannot form a covalent bond with the surface amino group in the dendrimer. The infrared spectra of CIIR/5 phr G2 PAMAM and CIIR/5 phr G2 PAMAM-H exhibited hydrogen bond peaks at 3000–3500 cm−1. Moreover, the hydrogen bond peaks formed by CIIR/5 phr G2 PAMAM-H were stronger than CIIR/5 phr G2 PAMAM, indicating that there were more hydrogen bonds formed in the CIIR/5 phr G2 PAMAM-H system.