Melting of nanoporous-crystalline and co-crystalline solution cast films of poly(2, 6-dimethyl-1, 4-phenylene) oxide. (16th July 2021)

• Record Type: Journal Article
• Authors: Nagendra, Baku; Golla, Manohar; Daniel, Christophe; Rizzo, Paola; Guerra, Gaetano
• Is Part Of: Polymer. Volume 228(2021)
• Publication Date: 2021-07-16
• Subjects: Differential scanning calorimetry -- Wide angle x-ray diffraction -- α and β forms -- Planar (c//) orientation -- Guest molecular volume; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; 547.7
• DOI: 10.1016/j.polymer.2021.123935
• Languages: English
• ISSNs: 0032-3861

Abstract

Abstract: The melting behavior of nanoporous-crystalline (NC) and co-crystalline (CC) PPO films is mainly studied by differential scanning calorimetry. For NC films, the dependence of melting behavior on α or β forms as well as on the chemical nature of the guest of precursor CC forms is explored. A relevant result of this contribution is that the use of PPO films with c // orientation also allows establishing melting temperatures of CC phases, being not accessible for other PPO samples. An additional relevant result is the achievement, by suitable annealing procedures on c // oriented CC films, of partially filled CC PPO films with melting temperature just below 300 °C, while NC PPO films always exhibit melting temperatures lower than 265 °C. The reported data, both on NC and CC films, also indicate that molecular volumes most suitable for guests of the α NC form of PPO are in the range 160–230 Å 3 . Graphical abstract: Image 1 Highlights: Co-crystalline (CC) phases between a polymer host (PPO) and low-molecular-mass guest molecules. Guest release from CC phases with c// orientation is shifted to higher temperatures. Annealing procedures allows establishing (for the first time) melting temperatures of CC PPO phases. c// oriented CC films with Tm just below 300 °C, while Tm values of PPO are generally lower than 265 °C. Tm data indicate that molecular volumes most suitable for guests of CC forms of PPO are in the range 160-230 Å 3 .