Abstract
Ultrafine fully vulcanized powdered natural rubber (UFPNR) has a promising application as a renewable toughening modifier in polymer matrices. In this work, the effects of acrylate coagents, which had different amounts of functional groups, on properties of UFPNR produced by radiation vulcanization and spray-drying was systematically investigated for the first time. Dipropylene glycol diacrylate (DPGDA), trimethylol propane trimethaacrylate (TMPTMA), and ditrimethylol propane tetraacrylate (DTMPTA) were used as coagents with two, three, and four acrylate groups, respectively. The radiation in the range of 250 to 400 kGy and coagent contents of up to 11 phr were used in the production process. Physical, chemical, and thermal properties of the UFPNR were characterized by swelling analysis, scanning electron microscopy, infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The properties of UFPNR produced by using different type and content of coagents were compared and discussed. The results revealed that UFPNR with the smallest particle size of 3.6 ± 1.1 μm and the highest thermal stability (Td5 = 349 °C) could be obtained by using DTMPTA, which had the highest amount of functional group. It was proposed that the coagent with the greater number of acrylate groups enhanced the crosslinking of natural rubber as it had more reactive groups. Finally, an application of UFPNR as a toughening filler in rigid PVC was demonstrated with 34% improvement of impact strength.
Highlights
We systematically investigated the effects of acrylate coagents, which had different numbers of functional groups, on the properties of Ultrafine fully vulcanized powdered natural rubber (UFPNR) produced by radiation vulcanization and spray-drying
For all types of coagents, the results demonstrated that when the content of coagents increased, there was a decrease in swelling ratio and increase of gel fraction of the UFPNR
UFPNR was successfully prepared by radiation vulcanization and spray drying
Summary
Natural rubber (NR) extracted from the Hevea brasiliensis tree is a natural and renewable material and a main component of cis-1,4-polyisoprene polymer. NR in its original form has a sticky characteristic and non-elastic properties [1,2,3,4]. To improve NR properties for extended applications, vulcanization has been applied to crosslink NR molecules, which makes NR heat stable and elastic [1]. Vulcanization of NR can be done by three main techniques using sulfur, peroxide, or radiation. Radiation vulcanization is becoming more favorable than the two conventional techniques as it possesses many promising advantages, namely a high degree of crosslinking, no oxidative degeneration in polymer, less energy consumption as it is operated at room temperature, and inherently clean technology [6,7]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
