Melt surface grafting of HDPE with mercaptoesters by thermolysis method

Abstract

High‐density polyethylene (HDPE) was graft functionalized with two different mercaptoesters in an inert atmosphere at 160°C under different experimental conditions by thermolysis method. The order of functionalization, crosslinking, and CC formation reactions were determined from the relative intensities of carbonyl stretching vibration and CH bending vibrations. FTIR, DSC, and TGA analytical tools were used to characterize mercaptoester‐functionalized HDPE. A plausible reaction mechanism is proposed here to explain the experimental results obtained. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers

FTIR study of the melt grafting of high density polyethylene with amino, sulfonate, and mercapto esters

“…The plot shows a straight line with the slope value of 1.28 which confirms the 1.25 order of the functionalization reaction with respect to the % weight of DCP or to that of DEMS. This is in accordance with our earlier publication [13]. The present result means that 1.25 mole of DEMS is required to functionalize 1 mole of HDPE.…”

“…The C-H bending vibration appears at 1469 cm . The peak is due to the OH stretching of DEMS: during the melt functionalization process, because of the hydrogen transfer reaction, the ester group is converted into the acid group [13]. Further, the bending vibration of the acid OH group can be confirmed by noting the small hump at 1627 cm -1 .…”

“…Anbarasan et al [13] explained a mechanism of the free radical grafting of thioester onto the HDPE backbone. A similar type of the mechanism is applied to the present system.…”

FTIR and thermal studies on esters grafted HDPE

“…The % of ester grafting was increased with the increase of (% weight of DCP). This is in accordance with our earlier publication 13 . The reason for this may be due to the availability of more and more free radicals, derived from DCP for grafting of EM onto HDPE.…”

“…where, W is the weight of non-cross linked polymer, C is the % weight of peroxide and 1.52 and 0.35 are calibration coefficients taken from our earlier publication 13 . DSC was recorded for the samples by using SDT 2960 simultaneous TGA and DSC, TA instruments under Nitrogen atmosphere at the heating rate of 10° C/min.…”