Low density polyethylene, LDPE composites

Effects of various chemical treatments such as sodium hydroxide, isocyanate, permanganate, and peroxide on the tensile properties of sisal fiber-reinforced low-density polyethylene (LDPE) composites were investigated. Sodium hydroxide treated fiber composites showed better tensile properties than xmtreated composites, and the enhancement was attributed to their rough surface topography and increased aspect ratio. It was reported that long chain structured cardanol derivative of toluene diisocyanate (CTDIC) treatment reduces the hydrophilic nature of the sisal fiber resulting in improved compatibility and dispersion. It was also reported that peroxide treatment of fiber showed maximum interfacial interactions [33]. 

M. J. Miah, Farid Ahmed, A. Hossain, A. H. Khan and Mubarak A. Khan. Study on Mechanical and Dielectric Properties of Jute Fiber Reinforced Low-Density Polyethylene (LDPE) Composites. Polymer-Plastics Technology and Engineering44 (8-9), 1443-1456. ... 

Plastic materials represent less than 10% by weight of all packagiag materials. They have a value of over 7 biUion including composite flexible packagiag about half is for film and half for botties, jars, cups, tubs, and trays. The principal materials used are high density polyethylene (HDPE) for botties, low density polyethylene for film, polypropylene (PP) for film, and polyester for both botties and films. Plastic resias are manufactured by petrochemical companies, eg. Union Carbide and Mobil Chemical for low density polyethylene (LDPE), Solvay for high density polyethylene, Himont for polypropylene, and Shell and Eastman for polyester. 

Note that, apart from the filler particle shape and size, the molecular mass of the base polymer may also have a marked effect on the viscosity of molten composites [182,183]. The higher the MM of the matrix the less apparent are the variations of relative viscosity with varying filler content. In Fig. 2, borrowed from [183], one can see that the effect of the matrix MM on the viscosity of filled systems decreases with the increasing filler activity. In the quoted reference it has also been shown that the lg r 0 — lg (MM)W relationships for filled and unfilled systems may intersect. The more branches the polymer has, the stronger is the filler effect on its viscosity. The data for filled high- (HDPE) and low-density polyethylene (LDPE) [164,182] may serve as an example the decrease of the molecular mass of LDPE causes a more rapid increase of the relative viscosity of filled systems than in case of HDPE. When the values (MM)W and (MM)W (MM) 1 are close, the increased degree of branching results in increase of the relative viscosity of filled system [184]. 

In order to illustrate the utility of model parameter interpretation, a data set containing NIR transmission spectra of a series of polymer films will be used [85]. In this example, films were extruded from seven different polymer blends, each of which was formulated using a different ratio of high-density polyethylene (HDPE) and low-density polyethylene (LDPE) where the blend compositions were 0, 2.5, 5,10, 25, 50 and 100% HDPE. NIR spectra were then obtained for four or five replicate film samples at each blend composition. Figure 12.18 shows the NIR spectra that were obtained. 

The types of polymeric membranes that have attracted much interest for analytical applications and are nowadays in common use are characterized as nonporous membranes such as low-density polyethylene (LDPE), dense PP and PDMS silicone rubbers, and asymmetric composite membranes... 

The composition of feed polymers also has an important effect on the properties of products. In the experimental work of Miskolczi et al. commercial waste plastics from the packaging, electronic and automotive industry and the agriculture were used as raw materials. The samples contained high-density polyethylene (HDPE), low-density polyethylene (LDPE), polypropylene (PP), ethylene-propylene copolymer (EPC), polystyrene (PS), polyamide 6.6 (PA 6.6) and polyvinyl chloride (PVC). 

Figure 1. Compositional dependence of the zero-shear viscosity for blends of a linear low density polyethylene (LLDPE) with (1) and (2) different LLDPE resins, and (3) with low density polyethylene, LDPE.

Composites have been prepared (10) through the polymerization of acetylene in low density polyethylene (LDPE) impregnated with the Shirakawa (11) catalyst. This approach may be potentially... 

Films. Three films were included in this study. Low density polyethylene (LDPE) was included as a representative polyolefin. It is not considered to be a barrier polymer. It has permeabilities to selected aroma compounds slightly higher than the permeabilities of polypropylene and high density polyethylene (1). A vinylidene chloride copolymer (co-VDC) film was included as an example of a barrier that is useful in both dry and humid conditions. The film was made from a Dow resin which has been designed for rigid packaging applications. A hydrolyzed ethylene-vinylacetate copolymer (EVOH) film was included as an example of a barrier film that is humidity sensitive. The polymer was a blend of resins with total composition of 38 mole% ethylene. 

U.S. Pat. No. 3,856,724 [28] describes a composite based on polypropylene or low-density polyethylene (LDPE) (density 0.92) and 5-45%, preferably 20%, by weight of a-cellulose (100-mesh flock) along with some additives. 

This prediction was found qualitatively valid for blends of low density polyethylene, LDPE, with linear low density polyethylene, LLDPE. At about 20 wt% of LDPE a sharp peak in the plot of a = d In T /d In Y (where Y = l/(f + 0.07) with f being the free volume fraction) vs. composition. This behavior was associated with the phase separation in the blends [Utracki and Schlund, 1987]. 

Fig. 11.4 Schematic of (a) an automotive floor composite (500-900gsm) comprising an upper tufted carpet structure, back-coated scrim, and lower, thermoformable low density polyethylene (LDPE) acoustic layer (b) a boot sideliner comprising a preformed composite faced with a textile.

Although the of PHA copolymers can be widely adjusted with the mcl-3HA comonomer composition, it is often set between 100 and 150°C to achieve the processing properties of typical commodity thermoplastics such as polyethylene. The crystallinity in this copolymer composition range is 20 0%, which produces very flexible low density polyethylene (LDPE) like materials. 

NaOH solution at 40 C, rinsed with water, dried by oven, then passed through a tank containing aqueous chromium(III) fumarato solution (Cr concentration = 0.24 mg/ml) at 70 C, dried again by oven, then passed, through the extrusion molding where molten low density polyethylene (LDPE) was heated to 300-330 C, the molten polyethylene was combined with aluminum foil to form composite film at the pressure of the roller. The thickness of polyethylene on aluminum was 0.08 mm. 

Supri and Ismail [46] prepared modified and unmodified low-density polyethylene (LDPE) and mixed it with water hyacinth fiber (WHF) composites by melt blending. Tensile test, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and water absorption behavior test of the composites were conducted. The NCO-polyol-modified LDPE/AAfHF showed higher tensile strength, modulus of elasticity, and water absorption resistance as compared to the unmodified LDPE/WHF composites. However, the elongation at break was better when the LDPE was immodi-fied. Moreover, the modified LDPE/WHF offered better thermal properties in comparison to the unmodified LDPE/WHF. The NCO-polyol was reported to create better dispersion of WHF in the LDPE matrix. 

Paraffin wax has been found to have an influence on the thermal and mechanical properties of low-density polyethylene (LDPE) [39,40]. It crosslinks to improve the mechanical properties of LDPE, short sisal fibres composites [42,43] and PVC. There is complete miscibility of the wax in LDPE at wax concentrations up to 10%, but only partial miscibility at higher wax concentrations. On blending an oxidised paraffin wax with LDPE, small wax concentrations improved the physical properties of the blends [40]. 

Zhou and co-workers [28] measured the electrical conductivity/resistivity of carbon black filled linear low-density polyethylene (LLDPE) and blends of LLDPE with ethylene-methylacrylate (EMA). The percolation threshold of the blended polymer composite was significantly lower than that of the LLDPE composite, although in an EMA composite the threshold is higher. This effect was due to preferential absorption of the carbon black into the LLDPE due to phase separation and immiscibility in low-density polyethylene (LDPE)/EMA blends. The viscosity of polymers in the blend... 

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