Degradation density polyethylene

Shear degradation is another parameter that is very difficult to quantify and it is not fully understood. Several studies have been made on this subject (16-19) and the topic has been reviewed (20). We have found in our own work (21) that NBS 1476, a low-density polyethylene, is very susceptible to shear degradation in the GPC column and that the amount of degradation that will occur is very dependent on both flow rate and the particle size of the packing. 

CATALYTIC DEGRADATION OF IGH DENSITY POLYETHYLENE AND POLYPROPYLENE INTO LIQUID FUEL IN A POWDER-PARTICLE FLUIDIZED BED... 

Catalytic degradation of high density polyethylene over post grafted MCM-41 catalyst kinetic study... 

In this study, post-synthetic metal grafting was used to incorporate A1 into MCM-41 (Al-MCM-41-P), which was probably the first attempt at the catalytic degradation of waste plastics. The objective of this study was to investigate the kinetic aspect of high-density polyethylene (HDPE) over Al-MCM-41-P. 

For a ToF-SIMS investigation of the surface oxidative degradation of low-density polyethylene (LDPE), the polymer was exposed to 1802 rather than 1602 in order to be able to readily discriminate oxygen introduced by the ageing process from that in the polymer prior to ageing [102], Figure 36 shows an example series of ToF-SIMS spectra from this investigation, which shows the clear separation of the lsO species from the lsO species. In the study, close correlation was observed between the intensity of the lsO carbonyl species determined by mid-infrared spectroscopy with the ToF-SIMS 180- peak intensity as a function of 1802 exposure time. ToF-SIMS spectra obtained from microtomed cross-sections showed no... 

The samples investigated initially were commercial high pressure low density, linear low density and high density polyethylenes and had properties given in Table 1. Solutions of these polymers were prepared in concentrations of 0.8 to 3.5 g/1 by dissolving the pol5rmer over a time period of two hours in an oven maintained at 145°C. To avoid degradation 0.05% 4,4 -thiobis(3-methyl-6-tert-butyl phenol) was used as an antioxidant in the solutions. 

The most fundamental work on polyethylene degradation is being done by A. C. Albertsson in Sweden(27,28,29,30,31) using elegant science with labelled polymers to measure the rate and quantity of carbon dioxide evolution from buried high and low density polyethylene films. Degradation occurs at about... 

Figure 3 % Degradation vs. time at different temperatures. Data at 64°C were obtained in glass and high density polyethylene (HDPE) bottles.

W. Ding, J. Liang, and L.L. Anderson, Thermal and catalytic degradation of high-density polyethylene and commingled post-consumer plastic waste. Fuel Process. Technol., 51, 47 (1997). 

R. Ochoa, H.V. Woert, W.H. Lee, R. Subramanian, E. Kugler, and PC. Eklund, Catalytic degradation of medium density polyethylene over silica-alumina supports. Fuel Process. Technol., 49, 119 (1996). 

F.S. Qureshi, M.B. Amin, A.G. Maadhah, and S.H. Hamid, Weather-induced degradation of linear low density polyethylene Mechanical properties. Polym. Plast. Tech. Eng., 28 (7 8), 649-662 (1989). 

McNeill, I.C. and Mohammed, M.H., A comparison of the thermal degradation behaviour of ethylene-ethyl acrylate copolymer, low density polyethylene and poly(ethyl acrylate), Polym. Deg. Stab., 1995,48, 175-187. 

Andersson, T., Holmgren, M. H., Nielsen, T., and Wesslen, B. (2005). Degradation of low density polyethylene during extrusion. IV. Off-flavor compounds in extruded films of stabilized LDPE. J. Appl. Polym. Sci. 95,583-595. 

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