High density polyethylene, HDPE additives

The two polymer substrates investigated as part of the study of DBDPO mixtures were polypropylene (PP) and linear high density polyethylene (HDPE). while both PP and HDPE decompose by similar random chain scission, radical mechanisms, chain transfer occurs much more teadily during the pyrolysis of PP because of the presence of the tertiary hydrogens. In addition, only primary chain end radicals are formed when the HDPE chain cleaves homolytically. Therefore, a comparison of the PP/DBDPO and the HDPE/DBDPO mixtures volatile product distributions was undertaken. 

Although some polymers may be satisfactory when used under the stress of static loads, they may fail when subjected to impact. The impact resistance, or resistance to brittle fracture, is a function of the molecular weight of a polymer. Thus uhmwpe is much more resistant to impact failure than general purpose high-density polyethylene (hdpe). The impact resistance of brittle polymers is also increased by the addition of plasticizers. Thus polyvinyl chloride (PVC), plasticized by relatively large amounts of dioctyl phthalate, is much less brittle than unplasticized rigid PVC. 

Parabens are approved for use in oral solution and suspensions at a concentration of 0.015% to 0.2% w/v. Due to their low solubility, the sodium salts of parabens are often used in aqueous formulations. The parabens are most effective in the pH range of 2 to 6, and their antimicrobial activity decreases with increasing pH. Additionally, they are very unstable at pH 8 or above in solution. Methyl paraben has also demonstrated incompatibility with sorbitol and may show some discoloration in the presence of iron. The absorption of methylparaben by plastics has been reported with the amount absorbed being dependent upon the type of plastic and vehicle. However, no absorption has been reported for low density polyethylene (LDPE) or high density polyethylene (HDPE) containers. Certain coloring agents such as yellow iron oxide, ultramarine blue, and aluminum silicate can extensively absorb ethyl paraben in simple aqueous systems, thus reducing its preservative efficacy. 

A wide range of plastics with different properties has been used in the construction of laboratory apparatus. In spite of the adsorption ability of the polymers and, therefore, the risk of analyte loss by adsorption on container walls, contamination arising from residual catalysts and additives used in their manufacture is the main problem. Among the most common plastics used in manufacturing laboratory containers are low-density polyethylene (LDPE), high-density polyethylene (HDPE), polypropylene (PP) and polytetrafluoro-ethylene (PTFE). 

Plastic polymers make up a high proportion of waste and the volume and range used is increasing dramatically. The two main types of plastic are thermoplastics which soften when heated and harden again when cooled and thermosets which harden by curing and cannot be remoulded. The six main plastics in municipal solid waste are, high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and polyethylene terephthalate (PET). In addition there are... 

This chapter covers fundamental and applied research on polyester/clay nanocomposites (Section 31.2), which includes polyethylene terephthalate (PET), blends of PET and poly(ethylene 2,6-naphthalene dicarboxy-late) (PEN), and unsaturated polyester resins. Section 31.3 deals with polyethylene (PE) and polypropylene (PP)-montmorillonite (MMT) nanocomposites, including blends of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE). Section 31.4 analyzes the fire-retardant properties of nanocomposites made of high impact polystyrene (HIPS), layered clays, and nonhalogenated additives. Section 31.5 discusses the conductive properties of blends of PET/PMMA (poly (methyl methacrylate)) and PET/HDPE combined with several types of carbon... 

The process can combine conventional glass fiber roving, aramid, or carbon fiber tows with TPs, most commonly polyethylene terephthalate (PET) and nylon (polyamide/PA). Other plastics used include polyphenylene sulphide (PPS), styrene-maleic anhydride (SMA), high-density polyethylene (HDPE), and polypropylene (PP). The TPs can take the form of pellets, chips, chunks, or shreds, and as the process uses hot-melt injection, no solvents or two-part systems are involved. Additives such as colorants and fillers can be used as required. 

Li et al. reported that immiscible high-density polyethylene (HDPE)/ poly(ethylene terephthalate) (PET) blends, prepared by means of melt extrusion with ethylene-butyl acrylate-glycidyl methacrylate (EBAGMA) terpoly-mer as a reactive compatibilizer, can exhibit shape memory effects [32]. They observed that the compatibilized blends showed improved shape memory effects along with better mechanical properties as compared to the simple binary blends. In the blend, HDPE acts as a reversible phase, and the response temperature in the shape recovery process is determined by of HDPE. The shape-recovery ratio of the 90/10/5 HDPE/PET/EBAGMA blend reached nearly 100%. Similar behavior was observed for immiscible HDPE/ nylon 6 blends [33]. The addition of maleated polyethylene-octene copolymer (POE-g-MAH) increases compatibility and phase-interfacial adhesion between HDPE and nylon 6, and shape memory property was improved. The shape recovery rate of HDPE/nylon 6/POE-g-MAH (80/20/10) blend is 96.5% when the stretch ratio is 75%. 

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