Crystallization of low-density polyethylene- and linear low-density polyethylene-rich blends

Abstract

The crystallization of a series of low‐density polyethylene (LDPE)‐ and linear low‐density polyethylene (LLDPE)‐rich blends was examined using differential scanning calorimetry (DSC). DSC analysis after continuous slow cooling showed a broadening of the LLDPE melt peak and subsequent increase in the area of a second lower‐temperature peak with increasing concentration of LDPE. Melt endotherms following stepwise crystallization (thermal fractionation) detailed the effect of the addition of LDPE to LLDPE, showing a nonlinear broadening in the melting distribution of lamellae, across the temperature range 80–140°C, with increasing concentration of LDPE. An increase in the population of crystallites melting in the region between 110 and 120°C, a region where as a pure component LDPE does not melt, was observed. A decrease in the crystallite population over the temperature range where LDPE exhibits its primary melting peaks (90–110°C) was noted, indicating that a proportion of the lamellae in this temperature range (attributed to either LDPE or LLDPE) were shifted to a higher melt temperature. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1009–1016, 2000

The Effect of Extrusion Processing Conditions and Polyisobutylene Concentration on the Properties of Polyethylene for Stretch and Cling Film Applications

“…Given that the cast films are quenched more rapidly than the blown films, the LDPE and LLDPE phases do not have time to develop separate crystalline regions when quenched and therefore exhibit a broad melting endotherm and a higher level of co-crystallisation of the LLDPE and LDPE. This would tend to confirm the work by Drummond et al [13] who reported co-crystallisation occurring in blends of LLDPE and LDPE. However, the film tear properties shown in Figure 7 suggest a higher degree of orientation in the blown films compared to the cast films.…”

Mechanical properties of wood-plastic composites made from various wood species with different compatibilisers

“…An alternative reason may be that EVOH does not interact with all parts of the polymer and therefore cancels out the positive reinforcement effects of the fibres, as described by Basson (2013). This was also highlighted by Drummond et al (2000) who stated that EVOH only facilitates interactions between the ethylene-rich areas of the LDPE and wood. The low and significantly different tensile strength of Beefwood composites with EVOH compatibiliser may also be caused by the high pH value of the wood, since the pH of wood affects a number of properties related to the quality of wood based composites (Hernández 2013).…”

Thermoplastic starch blends: A review of recent works

“…[1][2][3][4][5][6][7][8][9][10] and particularly in polyole fins; it helps in cost reduction and rising biodegrad ability of resultant composite as well as in increasing the rigidity (high modulus) [3] of the material. How ever, the starch concentration at which useful product can be obtained is therefore limited to a low range after which the materials properties suffer dramatically.…”