LDPE film

Linear Low Density Polyethylene. Films from linear low density polyethylene (LLDPE) resias have 75% higher tensile strength, 50% higher elongation-to-break strength, and a slightly higher but broader heat-seal initiation temperature than do films from LDPE. Impact and puncture resistance are also improved over LDPE. Water-vapor and gas-permeation properties are similar to those of LDPE films. 

Eor t7-limonene diffusion in a 50-pm thick vinyUdene chloride copolymer film, steady-state permeation is expected after 2000 days. Eor a 50- pm thick LDPE film, steady-state permeation is expected in less than one hour. If steady-state permeation is not achieved, the effective penetration depth E for simple diffusion, after time /has elapsed, can be estimated with equation 8. 

The commercial grades available in the 1970s used either zinc or sodium as the cross-linking ion and ranged in melt flow index from 0.4 to 14. The main application of the ionomer resins has been for packaging film. The polymer is particularly useful in composite structures to provide an outer layer with good heat sealability. The puncture resistance of film based on ionomer film has the puncture resistance of a LDPE film of twice the gauge. 

Table 3 UV-Embrittlement Times (EMT) of PP and LDPE Films Containing Different Concentrations of Antioxidants (processed in an internal mixer at 190°C and 150°C, respectively, and exposed to UV light in an accelerated sunlamp-blacklamp UV aging cabinet)...

Low-density polyethylene (LDPE) film for food packaging, etc. High-density polyethylene (HDPE) blow molded into bottles and containers... 

The concentration of the UV stabiliser 2 hydroxy-4-octoxybenzophenone in LDPE film was measured by... 

Degradation products of LDPE/(BHT, Chimassorb 944) after long-term exposure to compost, water and air (chemical hydrolysis at pH 5 and pH 7) at room temperature were examined by GC-MS [277] the structural changes in the LDPE film were monitored by DSC and SEC. Among the 79 low-MW degradation products identified by GC-MS the main components were... 

Mid-IR spectroscopy, alongside gravimetric and molecular weight determinations, has also been used to analyse the biodegradation by a thermophilic bacterium (isolated from soil) of an LDPE film [44], The mid-IR studies were undertaken using the ATR sampling technique on control samples, samples that had been UV irradiated, and samples that had been UV irradiated then incubated with bacteria. The study showed that the particular bacterial strain was capable of utilising standard and photo-oxidised polyethylene as the sole carbon source. 

LDL receptor (LDLR), 5.T89 L-DOPA, 2 560, 606 LDPE copolymers, 20 213-214. See also Low density polyethylene (LDPE) LDPE film, gels in, 20 229-230 LDPE homopolymer, 20 212 LDPE ionomers, 20 214 LDPE polymerization, peroxide initiators for, 20 218t... 

Saleem, M. Asfour, A.A. De Kee, D. 1989, Diffusion of organic penetrants through low density polyethylene (LDPE) films Effect of size and shape of the penetrant molecules. J. Appl. Polym. Sci. 37 617-625. 

Flat covers nonwoven PP, punched LDPE films. 

Usually, the PFR serves as a probe reaction for the study of the morphology of the matrix. This has been demonstrated by Weiss and co-workers in a series of recent articles on the photoreactivity of esters included in several polyethylene films. Low-density polyethylene (LDPE) films hosting 2-naphthyl esters bring about different selectivity in the PFR as compared with the reaction in solution. In addition, the selectivity is different if the polymer is stretched [286,287], Table 16 indicates the different product distributions upon irradiation of 2-naphthyl esters, depending on the nature of the solvent or matrix. The most striking fact is that irradiation of 2-naphthyl myristate leads to the coupling at the position 1 in ferr-butanol with 86% yield, whereas this product is absent in the irradiations in polyethylene films. Moreover, the product of coupling at position 3 is absent... 

Table 16 Product Distribution in the Irradiation of 2-Naphthyl Acylates in Solution and in LDPE Films...

Table 1 Permeabilities and diffusion coefficients for LDPE films ...

There have been more efforts to use blends such as Nova Chemicals Arcel (an ethylene styrene interpolymer in bead form) to create a more durable foam than EPS. EPP can be moulded into complex shapes, with the steam bonding of the beads (291). These packaging foams compete with polyolefin film products such as Jiffy foam (bubblewrap) and macrobubbles made by heat sealing 150 mm lengths of tubular LDPE film. As it is difficult or costly to recycle such foam products, in some countries there is a move towards biodegradable starch foams and moulded paperboard. 

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