Ethylene-propylene-diene monomer plasticization

TPEs from blends of rubber and plastics constitute an important category of TPEs. These can be prepared either by the melt mixing of plastics and rubbers in an internal mixer or by solvent casting from a suitable solvent. The commonly used plastics and rubbers include polypropylene (PP), polyethylene (PE), polystyrene (PS), nylon, ethylene propylene diene monomer rubber (EPDM), natural rubber (NR), butyl rubber, nitrile rubber, etc. TPEs from blends of rubbers and plastics have certain typical advantages over the other TPEs. In this case, the required properties can easily be achieved by the proper selection of rubbers and plastics and by the proper change in their ratios. The overall performance of the resultant TPEs can be improved by changing the phase structure and crystallinity of plastics and also by the proper incorporation of suitable fillers, crosslinkers, and interfacial agents. 

Knappe [10] described the use of DMA to check the plasticizer level of polybutadiene/natural rubber blends. DMA can also be used to look at coatings on elastomer parts, an example being a polyurethane coating on an EPDM (ethylene propylene diene monomer) bumper part, where the low temperature storage modulus can be a key to component toughness. 

For flexible sheeting, as single ply roofing use, PVC and ethylene-propylene-diene monomer (EPDM) are expected to be the main polymers used. For wall and floor coverings PVC is still expected to continue to dominate the construction market. PVC will be the main plastic used for pipe and conduit, wire and cable, profiles and flooring applications, while EPS will be mostly used in insulation. 

The polyolefins are those polymers based only on carbon and hydrogen, originating from monomers containing a double bond in the 1-position, sometimes called a-olefins. Principally, these include polyethylene, polypropylene, copolymers of polyethylene containing various comonomers such as 1-butene, 1-hexene, and 1-octene, ethylene-propylene monomer (EPM), and ethylene-propylene-diene-monomer (EPDM). All of these are plastics except EPM and EPDM, which are elastomers. 

Hard plastic pump with ethylene propylene diene monomer (EPDM) diaphragm 3 in. of Tygon tubing... 

Exterior door handles are another application that has turned to plastics to balance chemical resistance and mechanical properties. Many filled thermoplastics such as blends of PC and polybutylene terephthalate (PBT), polyethylene terephthalate (PET), and nylon have been tried or used in this application, with nylon as the clear wirmer. Exterior mirror housings likewise use many thermoplastic solutions such as ABS, PC/ABS, blends of polyphenylene oxide (PPO) and polystyrene (PS), nylon, blends of PP and ethylene propylene diene monomer (EPDM), and weatherable ABS. Again, nylon clearly dominates this application in terms of volume. Many other exterior parts continue to adopt thermoplastic solutions. Figure 14 shows an impingement shield constructed from LGF PP. 

Automotive industry waste provided another idea for a study [10]. Recycled plastics from bumpers are being applied in several areas, even as new bumpers [11, 12]. Thermal analysis was applied to the material used in discarded car bumpers, which came from standard grade automobiles of different brands. The recycled polymer composition was a polymeric blend of PP, ethylene-propylene-diene monomer (EPDM) and high-density polyethylene (HOPE). Differential scanning calorimetry (DSC) analysis (Figure 2.5) confirmed the presence of PP, and indicated HDPE and EPDM as ingredients in the formulation of car bumpers. 

An ethylene propylene diene monomer/poly (ethylene-co-vinyl acetate) (EPDM/ EVAc) blend has also been proven to exhibit the above observations in systems with benzene, toluene and xylene as probe molecules [64]. The reduction in solvent uptake was prominent when the EVAc content was increased, and the compositions became less rubbery or more plastic-like due to the semicrystalline nature of EVAc. The liquid sorption characteristics of sulfur- and peroxide-cross-linked 40/60 EPDM/EVAc blends can be explained by the nature of the S—S and C—C chemical bonds. 

Another illustration of the impact of these influences, such as increasing landfill taxes for general rubber goods products, is that more forms of waste rubber are being considered for recycling. One example of this is the recycling of post-industrial and postconsumer ethylene-propylene-diene monomer (EPDM) rubber membranes, which has received a great deal of attention in recent years as described in an article published in Rubber and Plastics News [5]. 

The second class is made up of elastomer/thermoplastic blends, abbreviated TEO. Typical of this class is a dispersion of 20-30 parts of rubber based on ethylene-propylene-diene monomer (EPDM) in a continuous phase of 70-80 parts of a plastic such as isotactic polypropylene. Partial covalent cross-linking of the... 

Thermoplastic polyolefins (TPOs) are composite blends of semicrystalline polypropylene and ethylene propylene copolymer (EPR) or ethylene propylene diene monomer (EPDM), widely used in the automotive industry for the production of plastic car parts such as bumper fascia [1]. Polypropylene, which is the major component in such blends, is an inexpensive, easily proccessible polymer, although its poor mechanical properties necessitate the addition of a rubber-dispersed phase. The added rubber acts as an impact modifier by imparting improved ductility, crack resistance, and impact strength to the resulting TPO [1-4]. The cost-effectiveness, light weight, processability, and resilience of TPOs have made them increasingly viable alternatives to steel for bumpers and other car parts. 

Abraham et al. [158] were the first ones to propose saturating commercially available microporous polyolefin separators (e.g., Celgard ) with a solution of lithium salt in a photopolymerizable monomer and a nonvolatile electrolyte solvent. The resulting batteries exhibited low discharge rate capability due to the significant occlusion of the pores with the polymer binder and the low ionic conductivity of this plasticized electrolyte system. Dasgupta and Jacobs [157,168] patented several variants of the process for the fabrication of bonded-electrode lithium-ion batteries, in which a microporous separator and electrode were coated with a liquid electrolyte solution, such as ethylene-propylene-diene (EPDM) copolymer and then bonded under elevated temperature and pressure conditions. This method required that the whole cell assembling process be carried out in scrupulously anhydrous conditions, which make this approach difficult, and expensive. 

Elastomers or rubbers are flexible materials that are mainly used in tires, hoses, and seals as adhesives or as impact modifiers of thermoplastics. They exhibit high resistance to impact, even at low temperatures at which materials increase their rigidity. Eor some of the applications (e.g., tires or hoses), these materials have to be slightly crosslinked once they are formed into the desired shape in order to impart them dimensional stability, since otherwise they tend to slowly flow. Elastomers are polymers that are used above their glass-transition temperature (Tg). Some examples of common elastomers are polybutadiene, which is used as an impact modifier of rigid plastics SBR (copolymer of styrene and butadiene), mainly used in tires EPDM (copolymer of ethylene, propylene, and a diene monomer, usually norbornene) NBR (copolymer of acrylonitrile and butadiene) and so on. 

Radiation-induced curing of plastic coatings has been discussed,8 and radiation-induced polymerization in the solid state reported.87 The radiation chemistry of epoxy-containing electron resists88 and polycondensation induced by ionizing radiation in the urea-formaldehyde system88 have been described. Radiation-induced copolymerization of the following pairs of monomers has been achieved ethylene-hexafluoropropylene,80 tetrafluoroethylene-propylene,81 tetrafluoroethylene-hexafluoropropylene,82 hexafluoroacetone-a-olefins,83 MMA-di- and tri-methacrylates,84 styrene-acrylonitrile,85 buta-1,3-diene-acrylonitrile,88 and acenaphthylene-vinylcarbazole.87... 

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