2:00 pm - 3:00 pm
A graduate exam seminar is a presentation of the student’s final research project for their degree.
This is an ALES PhD Final Exam Seminar by Reza Ahmadi. This seminar is open to the general public to attend.
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Meeting ID: 997 7159 3717
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Thesis Topic: Synthesis of Biobased Polyethers, Polyesters and Polyamides from Canola Oil Derived Monomers Using Microwave Irradiation
PhD with Dr. Aman Ullah.
Polymers are essential in modern life’s sustainable growth with their diverse applications in packaging, construction, automotive, electronic industries, etc. Nowadays, polymer industry mainly depends on petroleum resources as feedstock and energy source. Increased environmental concerns and limited petroleum resources have impelled industry and researchers to look for renewable feedstocks and alternative methods of polymer synthesis. Plant oils have been considered as prospective feedstocks for the polymer industry due to their worldwide availability and structural similarity to petroleum resources. Microwave irradiation has also emerged as an alternative heating technique for polymer synthesis. This thesis investigated the synthesis and characterization of different polymers from canola oil-derived monomers under conventional heating and microwave irradiation.
In the first study, 1-decene was polymerized to biopolyethers after chemical modification. 1-decene was first converted to 1,2-epoxydecane using m-chloroperoxybenzoic acid and then was subjected to ring-opening polymerization (ROP). Microwave epoxidation of 1-decene was optimized at 5 min (67% yield), whereas, the conventional epoxidation was completed at 60 min (> 93% yield). ROP of 1,2-epoxydecane using modified methyl aluminoxane catalyst resulted in the production of high-molecular weight biopolyethers (> 2 × 106 g/ mol). The microwave ROP improved polymerization yield (about 9.8%) and reduced the required amount of solvent by 30% compared to the conventional reaction. The melting temperature and decomposition temperature of the produced biopolyethers were 88°C and between 325 to 418 °C, respectively. The difference between the biopolyethers’ glass transition temperatures was explained by the microwave’s effect on the polymer’s tacticity.
The second and third studies investigated synthesis and characterization of two long-chain, unsaturated polyamides, PA (DMOD-PXDA) and PA (DMOD-DETA), from dimethyl 9-octadecenedioate (DMOD) and two different amines (p-Xylylenediamine and diethylenetriamine) under conventional heating and microwave irradiation. The melting temperature of polyamides was around 190 °C with higher values for the conventionally polycondensed ones. Polyamides’ films were also prepared, and their characteristics were evaluated. PA (DMOD-PXDA) films had tensile strengths of about 20 Mpa. The percent elongation at break of the film from conventionally polymerized PA (DMOD-PXDA) was 3 times higher than its microwave polymerized counterpart. Regarding PA (DMOD-DETA) films, the film from conventionally polymerized PA (DMOD-DETA) showed higher tensile strength but lower percent elongation at break compared to its microwave counterpart.
In the last study, a one-pot synthesis approach for producing a long-chain, unsaturated biopolyester using canola oil-based monomers (DMOD, its acid, and 1,2-epoxydecane) was developed. The polymerization was achieved by acid-epoxy addition of 9-octadecenedioic acid to 1,2-epoxydecane followed by polycondensation of the resulting biodiol with DMOD. Interestingly, the microwave acid-epoxy addition reduced the reaction time from 3 hrs in conventional heating to 30 min. The second step to produce biopolyester employed SnCl2 catalyst in a solvent-free media under high vacuum and conventional heating. The synthesized biopolyester showed comparable thermal properties to the commercial polyesters such as polyethylene terephthalate and polybutylene terephthalate.
Overall, this work developed rapid synthesis approaches for synthesizing high molecular weight biopolyethers and long-chain biopolyesters and polyamides with unsaturated motifs which are highly attractive from both industrial and academic points of views.