Enhanced Poly(propylene carbonate) with Thermoplastic Networks: A Cross-Linking Role of Maleic Anhydride Oligomer in CO2/PO Copolymerization

Abstract

Cross-linking is an effective way to enhance biodegradable poly(propylene carbonate) (PPC) from CO2 and propylene oxide (PO). Cross-linked PPC can be prepared by one-step terpolymerization of multifunctional third monomers with CO2 and PO. However, few such third monomers are available. Each molecule of maleic anhydride oligomer (MAO) contains more than two cyclic anhydride groups. Here, we use it to synthesize PPC with cross-linked networks by adding a small quantity of MAO (0.625–5 wt% of PO) in CO2/PO copolymerization that was catalyzed by zinc glutarate. The formation of networks in the prepared copolymers was confirmed by the presence of gel in copolymers combined Fourier transform infrared spectroscopy (FT-IR), 1H NMR, and the improved mechanical properties. The 5% weight-loss degradation temperatures and maximum weight-loss degradation temperatures greatly increase up to 289.8 °C and 308.8 °C, respectively, which are remarkably high when compared to those of PPC. The minimum permanent deformation of the copolymers closes to 0, while that of PPC is 173%. The maximum tensile strength of the copolymers is 25.5 MPa higher than that of PPC, reaching 38.4 MPa, and it still has some toughness with the elongation at break of 25%. The above phenomena indicate that MAO that was inserted in PPC chains play a cross-linking role, which results in enhanced thermal stability, dimensional stability, and mechanical strength, comprehensively.

Cross-Linked Networks in Poly(propylene carbonate) by Incorporating (Maleic Anhydride/cis-1,2,3,6-Tetrahydrophthalic Anhydride) Oligomer in CO2/Propylene Oxide Copolymerization: Improving and Tailoring Thermal, Mechanical, and Dimensional Properties

“…The above characteristics demonstrate that the copolymers have more rigid and stronger resistance to strain and deformation than PPC at higher temperatures, where the formed cross-linked networks in the PPC matrix by introducing the MA/THPA oligomer play an important role in restricting the PPC chain movement. Compared with the case of the MA oligomer as the third monomer, 51 where the dimensional stability did not reach 0 when the amount of the MA oligomer is 3.74 wt % of PO, the permanent deformation rate reaches 0 when the MA/THPA feed is 3 wt % of PO, and the test temperature is 5 °C higher than the former. Therefore, when a rigid monomer THPA is introduced into the MA co-oligomer, it is more beneficial to improve the dimensional stability.…”

“…A zinc glutarate (ZnGA) catalyst was synthesized following the literature procedure. 51 Toluene, chloroform, and methanol were dried over 0.4 nm molecular sieves for more than 24 h before use. Benzoyl peroxide (BPO) was recrystallized from a mixed solvent of chloroform and methanol before use.…”

“…We have tried to use a maleic anhydride oligomer as the third monomer to prepare cross-linked PPC. 51 We speculate that the mechanical strength and toughness of the copolymer can be tailored by the co-oligomer from different rigid or flexible monomers and MA. In this work, we select a relatively rigid monomer, cis -1,2,3,6-tetrahydrophthalic anhydride (THPA), to prepare a MA/THPA oligomer, and use it to copolymerize with PO and CO 2 to synthesize PPC with cross-linked networks in one pot.…”

“…However, it is difficult to further verify the above finding because there are not many multifunctional small molecules, commercially, that can participate in CO 2 /PO copolymerization, and their custom synthesis is not economical. We have tried to use a maleic anhydride oligomer as the third monomer to prepare cross-linked PPC . We speculate that the mechanical strength and toughness of the copolymer can be tailored by the co-oligomer from different rigid or flexible monomers and MA.…”

Effect of Spinning Parameters on Pla/PPC/Curcumin Microfiber Diameter: an Investigation via Response Surface Methodology

“…The physical properties of PLA can be attuned for specific applications by blending (solvent or melt blending techniques) [5] with biodegradable polymers such as polypropylene carbonate (PPC) [6]. PPC is produced through a copolymerization process of CO2/propylene oxide (PO) [7]. The resulting copolymer chains are comprised of homopolymer propylene oxide and alternating carbon dioxide and propylene segments [8].…”