Font Size: a A A

Study On The Decoloring And Modified Functional Of Polyethylene Wax From Pyrolysis

Posted on:2015-05-28Degree:MasterType:Thesis
Country:ChinaCandidate:S T MengFull Text:PDF
GTID:2181330431485216Subject:Organic Chemistry
Abstract/Summary:PDF Full Text Request
As a kind of commonly used additive during material processing, polyethylene wax is widely used in industrial production. But it has some disadvantages, for example, it is difficult to infiltrate because of its low surface tension, and it is incompatibility with many kinds of polar material. Therefore, the study of polyethylene wax modification has an important significance.In this paper firstly the decolorization of two kinds of industrial crude wax was studied through stagewise adsorption refining based on zeolite as adsorbent. The effects of adsorbent amounts, adsorbent input number, adsorbent temperature, adsorbent time and decolorization number on decolorizing polyethylene wax were investigated. The structure and color of decolorized crude wax were characterized with the fourier transform infrared spectroscopy (FT-IR), atomic absorption spectrophotometer (AAS) and the whiteness meter. And a discussion in the reasons of the polyethylene wax that came from waste plastic by pyrolysis has been given. The results showed that the crude wax of the color materials did not contained aromatic cyclic structure, and the fragmentation pathway of waste polyethylene waste was as the random pyrolysis reaction. The color of the crude wax related with the structures of the impurities and the remaining metal elements came from the catalytic system, the unsaturated hydrocarbon and the metal elements could be removed by adsorbent adsorption. The whiteness value increased from54.3%and70.8%to15.4%and17.9%when the amount of adsorbent was10%, the adsorbent input number was3times, the reaction temperature was90℃, the adsorbent time was8h, and decolorization number was3times; the results of FT-IR showed that the structure of crude wax was not changed after being decolorized; the results of AAS showed that with the increase of the decolorizing number, the content of the metal elements decreased. When the decolorizing number was3times, the content of Ti、Mg、 Al in crude wax A decreased from0.5901%,1.1499%,0.3828%to0.2922%、0.7547%、0.2507%; the content of Ti、Mg、Al in crude wax B decreased from0.5122%、0.9518%、 0.3387%to0.1041%、0.6134%、0.2721%.Secondly, the carboxyl chemical modification of polyethylene wax was studied through catalytic oxidation of solution by using cobaltous acetate as catalyst and benzoyl peroxide as initiator. In this way the oxygen-containing functional groups were introduced to the carbon chain to improve the polarity of products. The production of acid value and contact angle of the samples were characterized during the experiment, the modified polyethylene wax was characterized by FT-IR, thermo-gravimetric analysis (TG) and X-ray diffraction (XRD). The results showed that A and B crud wax could obtain oxidized wax with the acid value were16.26mg KOH·g-1and16.17mg KOH·g-1, and the contact angle were72.4degree and74.6degree when the amount of catalyst was1%, the amount of initiator was1%, the reaction time was8h, and the reaction temperature was90℃; the results of TG showed that with the increase of the acid value, the thermal stability of oxidized wax decreased; the results of XRD showed that the crystallinity of polyethylene wax decreased after carboxyl modification.Finally, the oxidized polyethylene wax made from carboxyl modification were conducted hard modification. The results showed that with the addition of increase of the rare earth metal oxide dosage, the penetration decreased, the penetration of hard modified product was2.82×10-1mm when the reaction temperature was90℃, reaction time was3h, and rare earth metal oxide dosage was2.5%, when the rare earth metal oxide dosage continued to increase, the penetration increased.
Keywords/Search Tags:polyethylene wax, forming color, decolorization, carboxylation, catalyticoxidation
PDF Full Text Request
Related items