Ethylene-propylene-diene stabilization

Ozonc-rcsjstant elastomers which have no unsaturation are an exceUent choice when their physical properties suit the appHcation, for example, polyacrylates, polysulfides, siHcones, polyesters, and chlorosulfonated polyethylene (38). Such polymers are also used where high ozone concentrations are encountered. Elastomers with pendant, but not backbone, unsaturation are likewise ozone-resistant. Elastomers of this type are the ethylene—propylene—diene (EPDM) mbbers, which possess a weathering resistance that is not dependent on environmentally sensitive stabilizers. Other elastomers, such as butyl mbber (HR) with low double-bond content, are fairly resistant to ozone. As unsaturation increases, ozone resistance decreases. Chloroprene mbber (CR) is also quite ozone-resistant. 

By rapid expansion of supercritical propane solution (RESS), and isobaric crystallisation (ICSS), isotactic polypropylene and ethylene-butylene copolymers were precipitated from the supercritical solution. The RESS process produced microfibres with a trace of microparticles, while the ICSS process produced microcellular products. Improvement in thermal stability was achieved by first synthesising a thermoplastic vulcanisate from polypropylene and ethylene-propylene-diene terpolymer from a supercritical propane solution, followed by RESS. 28 refs. 

Low-temperature solution processes are state-of-the-art for the production of ethylene/propylene or ethylene/propylene/diene elastomers (EPDR or EPDM). A continuous stirred-tank reactor (CSTR) or a series of two or even more such reactors is used [2]. n-Hexane, n-heptane, or Ce, C7 fractions are the solvents. Catalyst, co-catalyst and other compounds are introduced with the solvent into the reactor. The monomers (ethylene, propylene) are injected as gases other olefins are introduced in liquid form. The polymerization process runs around 50 °C and at pressures up to 2 MPa. Downstream the catalyst/co-catalyst system is deactivated and their residues are dissolved in dilute acid or aqueous NaOH. The copolymer is stabilized with an antioxidant. Steam treatment removes the rest of the solvent and monomers, and agglomerates the product to crumbs. These crumbs are then dried and finished to bales or pellets. 

Effects of maleated ethylene-propylene diene rubber (EPDM) on the thermal stability of pure polyamides, and polyamide/EPDM and polyamide/poly (ethylene terephthalate) blends kinetic parameters and reaction mechanism/Zl. Vieira, V.L. Severgnini, D.J. Maasra MS. Soldi, E.A Pinheiro, AT.N. Pires and V. ScAAilPolymer degradation and stability (2001), 74 1 151-157. 

Linear-Low Density Polyethylene (LLDPE) and Ethylene -Propylene Diene (EPDM) Stabilization. Prevention of discoloration of LLDPE and EPDM are prime objectives in addition to thermal stabilization. While thermal stabilization is readily achieved by the use of phenolic antioxidants, prevention of discoloration requires a co-additive such as a phosphite. 

In this paper, we wish to report two different types of elastomer blends, ethylene-propylene-diene terpolymer/polyacety-lene and styrene-diene triblock copolymer/polyacetylene, in the hope that the stability of polyacetylene might be improved by... 

In order to improve the stability of polyacetylene, polyacetylene was blended with ethylene-propylene-diene terpolymer. Subsequently, the resulting EPDM/PA blend was crosslinked with y-radiation. Upon doping with iodine, the conductivity of the blend was found to be in the range 10-100 SI-1 cm-. It was found that the conductivity of the crosslinked blend decayed more slowly compared to that of either the uncrosslinked blend or homopolyacetylene. 

This chapter reports the results of the literature that concerns the photooxidation of polymer nanocomposites. The published studies concern various polymers (PP, epoxy, ethylene-propylene-diene monomer (EPDM), PS, and so on) and different nanofillers such as organomontmorillonite or layered double hydroxides (LDH) were investigated. It is worthy to note that a specific attention was given to the interactions with various kinds of stabilizers and their efficiency to protect the polymer. One of the main objectives was to understand the influence of the nanofiller on the oxidation mechanism of the polymer and on the ageing of the nanocomposite material. Depending on the types of nanocomposite that were studied, the influence of several parameters such as morphology, processing conditions, and nature of the nanofiller was examined. 

The photooxidation of vulcanized ethylene-propylene-diene monomer/montmor-illonite nanocomposite as well as EPDM/nanocomposite with stabilizers was recently reported [105]. The photooxidation products were not changed in the presence of the nanofiller. However, the presence of MMt was observed to dramatically enhance the rate of photooxidation of EPDM with a shortening of the oxidation induction time, leading to a decrease in the durability of the nanocomposites. On the other side, it was observed that addition of stabilizers, either Tinuvin P or 2-mercaptobenzimidazole, was efficient in inhibiting the degradation effect of MMt. 

Martinez-Barrera, G., Lopez, H., Castano, V. M., Rodriguez, R., Studies on the rubber phase stability in gamma irradiated polystyrene-SBR blends by using FT-IR and Raman spectroscopy. Radiation Physics and Chemistry 2004,69,155-162. Abou Zeid, M. M., Rabie, S. T., Nada, A. A., Khalil, A. M., Hilal, R. H., Effect of gamma irradiation on ethylene propylene diene terpolymer rubber composites. Nuclear Instruments and Methods in Physics Research Section B Beam Interactions with Materials and Atoms 2008,266,111-116. 

Zaharescu, T., Assessment of compatibility of ethylene-propylene-diene terpolymer and polypropylene. Polymer Degradation and Stability 2001,73,113-118. 

TPO materials are defined as compounds (mixtures) of various polyolefin polymers, semicrystalline thermoplastics, and amorphous elastomers. Most TPOs are composed of polypropylene and a copolymer of ethylene and propylene called ethylene—propylene rubber (EPR) [2]. A common rubber of this type is called ethylene propylene diene monomer rubber (EPDM), which has a small amount of a third monomer, a diene (two carbon-carbon double bonds in it). The diene monomer leaves a small amount of unsaturation in the polymer chain that can be used for sulfur cross-linking. Like most TPEs, TPO products are composed of hard and soft segments. TPO compounds include fillers, reinforcements, lubricants, heat stabilizers, antioxidants, UV stabilizers, colorants, and processing aids. They are characterized by high impact strength, low density, and good chemical resistance they are used when durability and reliability are primary concerns. 

Stability (see Table 12.2). R talc is effective with ethylene propylene diene monomer (EPDM) and ethylene propylene rubbers (EPR) but not as effective with metallocene elastomers containing TPOs. Recently, Clark [11] presented evidence of improvements in scratch and mar resistance when talc is grafted to TPO. The need for higher performance materials will drive the development of new surface modification technologies [3]. 

Zahaiescu, T., Ferani, E., Podina, C. Thermal stability of ethylene propylene-diene monomer/divinylbenzene systems. Polym. Degrad. Stab. 87, 11-16 (2005)... 

Xiubin, Z., Haiyan, Z., Jin, L., Liping, L., Qiguang, W. Thermal conductivity and thermal stability enhancement of ethylene propylene diene methylene with carbon nanotube. J. Reinf. Plast. Compos. 33, 767-774 (2014)... 

H. NabU, H. Ismail, Enhancing the thermal stability of natural rabber/recycled ethylene-propylene-diene mbbo" blends by means of introducing pre-vulcanised ethylene-propylene-diene mbber and electron beam irradiation. Materials Design, ISSN 0261-3069 56 (April 2014) 1057-1067. http //dx.doi.Org/10.1016/j.matdes.2013.12.020. 

H. Nabil, H. Ismail, A.R. Azura, Optimisatioii of accelerators and vulcanising systems on thermal stability of natural rubber/recycled ethylene—propylene-diene-monomer blends. Materials Design, ISSN 0261-3069 53 (January 2014) 651-661. http //dx.doi. org/10.1016/jjnatdes.2013.06.078. 

Uses vulcanizing accelerator sulfur dyes pharmaceuticals floatation agent acid inhibitor intermediate for organic synthesis accelerator and activator for chloroprene rubber and ethylene-propylene-diene terpolymers as heat stabilizer in PVC adhesive-tape backing A... 

Polycarbonate can be blended with polyethylene (PE). Bloiding PC with PE has found many uses with a combination of a high level of heat resistance and dimensional stability as well as noncorrosive properties and ease of moldabihty. It is deficient in its tendency to craze and crack under the effects of contact with organic solvents such as gasoline. The failure mechanism of a crazed PC would be brittle fracture ratha- than ductile fracture. Blending PC with low density polyethylene (LDPE) and with linear low density polyethylene (LLDPE) or with ethylene propylene diene monomer (EPDM) rubbo improves the chemical resistance of the product to solvents. 

Kuriakose et al. mentioned that the reduction of the molecular weight of NR by mastigation" improved the processability of NR/PP thermoplastic blends. It was also observed that quinoline imparts better ageing resistance than imidazole when used as antioxidants in the blend. Another study observed that the highest thermal stability is attained with the addition of ethylene-propylene diene rubber to the NR/PP blend." TPEs can also be developed from recycled rubber (PP/RR) and Ismail and Suryadiasnsyah observed that its thermal stability was higher than that of PP/NR." " ... 

In one study, rPP and recycled polyethylene (rPE) were blended with two compatibilisers, polyethylene-grafted-maleic anhydride (PE-g-MA) and ethylene propylene diene monomer (EPDM) copolymer, and OMMT [56]. Scanning electron microscopy (SEM) micrographs showed that the blend with EPDM exhibited a better compatibilisation than PE-g-MA. The presence of OMMT caused an increase of the storage modulus and loss modulus additionally, OMMT improved the thermal stability. 

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