Research Plan

Stage 1: Optimization of existing synthetic protocols of polymers and their chemical modification

First, we will optimize the synthesis parameters for the polymers developed by the project leader in the previous young researcher project [poly(benzofuran-co-arylacetic acid), poly(tartronic-co-glycolic acid) and polytartaric acid], by changing some reaction parameters (time, temperature). Furthermore, alternative innovative synthetic methods (UV, microwave irradiation or even enzymatic reactions) will be applied for improving the polymer chain length.

Another step in this stage will be the investigation in how far the introduction of functional groups or small molecules can influence the thermal conductivity of the resulting polymer. Another important study will be performed to achieve changes in the thermal conductivity by crosslinking reactions of the three mentioned hydroxyl-containing polymers.

Different crosslinking agents will be applied, such as: poly(ethylene glycol) diglycidyl ether, 1,4-butanediol diglycidyl ether, tris(2,3-epoxypropyl) isocyanurate, 4-aminophenyl sulfone, different diamines or epoxidized vegetable oils) depending on the type of functional groups in the polymer chain. For example, amino resins serve as crosslinking agents for hydroxyl, carboxyl, and amide functional polymers.

Stage 2: Copolymerization reaction of the polymers

Copolymerization offers flexibility concerning possible monomers and a great diversity of polymeric products and composition drift, which may need to be minimized or exploited in a controlled way for specific structure–property relationship.

In this step of the project, we will develop new types of copolymers by performing the polymerization reaction of mandelic acid, tartaric acid and tartronic acid in the presence of other monomers, such as other α-hydroxyacids, ethylene glycol, glutamic acid, etc.  which can be polymerized under similar conditions (heating and without solvent) resulting in an as called random copolymer. In the latter case we will prepare block copolymers by covalently linkage between two different polymer homopolymers chains, the covalent bond will be created between the functional groups present on the hompolymers chain.

In this case we will take into consideration polymers that we have experiences from earlier studies (functionalized polypyrrole, different functionalized polyacrylates, polyethylenimine, or other known polyesters etc.). The resulting copolymers will be thoroughly structurally investigated by using several types of spectroscopies, which will provide complementary information about the copolymer structure.

Stage 3: Preparation of polymer composites

Polymers are the preferred insulating materials for several electrical applications due to their ease of production, lightweight, and low cost. However, their low thermal conductivity constitutes a bottleneck and efforts are made in order to increase it. An approach to improve heat transfer through polymers is the inclusion of fillers with relatively high thermal conductivity.

This project aims to use the prepared polymers and their crosslinked derivatives to embed different inorganic particles or nanoparticles (iron oxide nanoparticles, boron nitride, zinc oxide, aluminium oxide, copper oxide (I), metal nanoparticles etc.). Even when the intrinsic thermal conductivity of the inorganic nanoparticles is available, the wide variation in filler shape, size,  distribution, and orientation makes it difficult to predict the thermal conductivity of the composites.

Therefore, this will be an interesting study. After the preparation of the polymeric composites, we will have an extensive morphological and structural investigation. In this case, we will use SEM-EDX to determine the particle distribution inside the polymeric network and the elemental composition of the polymeric composites.