Modification of atactic polypropylene to prepare emulsions by oxidation in melt

Abstract

SynopsisOxidation of atactic polypropylene (APP) obtained as by product from polypropylene production is studied in melt to obtain polymers which are easily emulsified by commercial emulsifiers. The experiments are done using a stirred, jacketed glass reactor and the relevant heating, air-feeding, and sampling attachments. Oxidation is followed by the change of carbonyl absorbance, iodine number, acid number, molecular weight, and melt flow index (MFI) by time. The relevant tests are done by infrared (IR) spectroscopy and gel permeation chromatography (GPC) and standard tests with minor modifications are applied. It is found that as temperature, air flow rate, and mixing speed are increased, higher oxidation rates are obtained. It is also found that initiator types and concentrations used are not as effective as the above parameters. By oxidation as molecular weight reduces, molecular weight distribution narrows. Correlation between MFI, iodine number, and molecular weight of the oxidized APP is also made for easy follow-up of oxidations. In addition, it is found that for easy and stable emulsions, APP must be modified by oxidation to iodine number and MFI higher than 30 mg/g and 3.5, respectively.

Production and Characterisation of Multifilament Yarns Made from Polypropylene Containing Small Amounts of Oxidised Polypropylene

“…Previous studies have shown that the oxidation of PP involves mainly chain scission and decreases the molecular weight. [11][12][13] This explains the increase of MFI in the OPP granules.…”

“…[11][12][13] However, it is impossible to establish more precisely the exact nature and relative contribution of each species from these spectra. These correspond to products having -OH (alcohol, hydroperoxides, acids, etc., at 3200-3600 cm -1 ) and >C=O groups (ketones, acids, esters etc., at 1700-1800 cm -1 ).…”

“…Due to the presence of tertiary hydrogen atoms on PP, this polymer is susceptible to oxidation. 11,12,13 The present investigation deals with the formation of polar groups in PP fibres through blend fibre production from virgin PP granules and small amounts of oxidised polypropylene (OPP) granules. [6][7][8][9][10] The oxidation of PP leads to the formation of oxygen-containing groups, which greatly affect the surface polarity and the adhesion properties of the polymer.…”

“…[6][7][8][9][10] The oxidation of PP leads to the formation of oxygen-containing groups, which greatly affect the surface polarity and the adhesion properties of the polymer. 11,12,13 The present investigation deals with the formation of polar groups in PP fibres through blend fibre production from virgin PP granules and small amounts of oxidised polypropylene (OPP) granules. The thermal properties and some physical characterisation of the multifilament yarns have been studied.…”

Oxidation of Polypropylene Homopolymer in the Molten State in Presence of Air

“…The presence of tertiary carbons in isotactic polypropylene polymer matrix enhances greatly its oxidation possibilities [1][2][3][4][5][6][7][8]. The oxidation of polypropylene (PP) will change physical and mechanical properties of the polymer such as surface polarity, surface tension and adhesion of the polymer (9)(10)(11)(12)(13)(14).…”