Synthesis, Optical, Thermal and Structural Characteristics of Novel Thermocleavable Polymers Based on Phthalate Esters

Ary R Murad; A Iraqi; Shujahadeen B Aziz; Sozan N Abdullah; Rebar T Abdulwahid

doi:10.3390/polym12122791

Synthesis, Optical, Thermal and Structural Characteristics of Novel Thermocleavable Polymers Based on Phthalate Esters

Polymers (Basel). 2020 Nov 25;12(12):2791. doi: 10.3390/polym12122791.

Authors

Ary R Murad¹, A Iraqi², Shujahadeen B Aziz^{3

4}, Sozan N Abdullah⁵, Rebar T Abdulwahid^{3

6}

Affiliations

¹ Department of Pharmaceutical Chemistry, College of Medical and Applied Sciences, Charmo University, Chamchamal 46023, Iraq.
² Department of Chemistry, University of Sheffield, Sheffield S3 7HF, UK.
³ Hameed Majid Advanced Polymeric Materials Research Lab., Department of Physics, College of Science, University of Sulaimani, Qlyasan Street, Sulaimani 46001, Iraq.
⁴ Department of Civil engineering, College of Engineering, Komar University of Science and Technology, Sulaimani 46001, Iraq.
⁵ Department of Chemistry, College of Science, University of Sulaimani, Qlyasan Street, Sulaimani 46001, Iraq.
⁶ Department of Physics, College of Education, University of Sulaimani, Old Campus, Sulaimani 46001, Iraq.

Abstract

In this work three novel phthalate-based thermocleavable copolymers, PBTP-11, PBTDTP-11 and PFDTP-11 have been designed and synthesized. PBTP-11 and PBTDTP-11 were prepared by copolymerizing distannylated bithiophene without or with flanked thienyl groups as the electron-donor units with dibrominated secondary phthalate ester as the electron-acceptor units. PFDTP-11 was prepared by copolymerizing distannylated fluorene flanked by thienyl groups as the electron-donor moieties with dibrominated secondary phthalate ester as the electron-acceptor moieties. All polymers were prepared via the Stille polymerization. The impact of two different electron-donor units on the solubility, molecular weights, optical properties, thermal and structural properties of the resulting polymers were investigated. PFDTP-11 had the highest average molecular weight (M_n = 16,400 g mol^-1). The polymers had E_g in the range of 2.11-2.58 eV. After thermal treatment, the E_g of the polymers were reduced by around 0.3-0.4 eV. This significant control over bandgap is promising and opens a gate towards commercializing these copolymers in energy harvesting devices such as solar cells. TGA data showed weight loss at around 300 °C, corresponding to the elimination of the secondary ester groups. After annealing, the soluble precursor polymers were transformed into active phthalic anhydride polymers and the resulting films were completely insoluble in all solvents, which shows good stability. Powder XRD studies showed that all polymers have an amorphous nature in the solid state, and therefore can be employed as electrolytes in energy devices.

Keywords: UV-vis study; XRD study; phthalate esters; thermal analysis; thermocleavable polymers.