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

Abstract

Poly(propylene carbonate) (PPC) from CO 2 and propylene oxide (PO) has wide potential applications as a degradable “plastic”. However, the thermal stability and mechanical properties of PPC cannot meet most of the application requirements. Herein, we focus on improving these properties. A (maleic anhydride/ cis -1,2,3,6-tetrahydrophthalic anhydride) (MA/THPA) oligomer containing several cyclocarboxylic anhydride groups, which can copolymerize with PO, has been readily synthesized and used as the third comonomer to prepare PPC with cross-linked networks. The gel contents increase from 16 to 42% with increasing MA/THPA oligomer feed contents from 0.5 to 4 wt % of PO. The formation of cross-linked networks in PPC greatly improves the thermal, mechanical, and dimensional properties. The 5% weight-loss degradation temperature increases from 217 °C to nearly 290 °C before and after cross-linking, which ensures that PPC does not decompose in melt processing. The tensile strength of the copolymer is in the range of 22.2–44.3 MPa with elongation at break of 11–312%. The maximum tensile strength is improved by 143% compared to that of PPC. When the MA/THPA oligomer feed is above 3 wt % of PO, the hot-set elongation of the copolymer at 65 °C decreases more than 10 times when compared with that of PPC, and the permanent deformation is close to 0, while it is 145% for PPC. The dimensional stability is improved sharply. It can overcome the cold flow phenomenon of PPC. The improvement of the above comprehensive properties is of great significance to the practical application of PPC in various fields.

Cobalt-catalysed nucleophilic fluorination in organic carbonates

“…Interestingly, at prolonged reaction times the initial solution solidifies, thus suggesting that the polymerization of PC may occur. 22–24 This behaviour was detected for all the substrates to some degree, but it is more noticeable for isovaleryl chloride (entries 4 and 5, Table 1), in which case full conversion cannot be achieved. However, the use of PC allows for the straightforward isolation of the fluoride via vacuum distillation (see preparative synthesis of isovaleryl fluoride in the ESI†).…”

“…Interestingly, at prolonged reaction times the initial solution solidifies, thus suggesting that the polymerization of PC may occur. [22][23][24] This behaviour was detected for all the substrates to some degree, but it is more noticeable for isovaleryl chloride (entries 4 and 5, Table 1), in which case full conver- a Yields calculated by 19 F NMR using fluorobenzene as internal standard. b Room temperature (2.5 or 1.1 eq.…”

Novel elastic rubbers from CO2-based polycarbonates

“…This could be ascribed either to the steric hindrance of the aliphatic lateral chains, which could limit the accessibility of the pendant double bonds thus inhibiting their reaction with DCP and with each other, and/or to the insufficient incorporation of unsaturated groups. 50,51 On the other hand, the terpolymers prepared with at least 20% of pendant terminal unsaturations were successfully cross-linked yielding solid elastic rubbers (Fig. 5 and Table 4).…”

“…However, the materials were also found to be breakable as a result of repeated handling, probably due to the low molecular weight of the parent terpolymers before undergoing cross-linking. 33 The prepared elastic rubbers were then characterised to determine their degree of cross-linking by means of gel-content tests (Table 4), 44,51 showing a rather similar high degree of crosslinking (≥77%). The highest gel content (89%) and thus the highest degree of cross-linking was achieved with the elastic rubber based on the terpolymer prepared from the reaction of CO 2 with 1,2-epoxydecane and AGE (80 : 20), and this value was very similar to the gel content of the elastic rubber based on the copolymer of CO 2 and AGE (Table 4), suggesting that the incomplete cross-linking was not caused by the long alkyl lateral chains that are present in the terpolymer.…”

Research and Application of Polypropylene Carbonate Composite Materials: A Review

“…Chemical modification requires the introduction of appropriate units into the polymer, starting from the microstructure, so that a chemical reaction can take place to copolymerize the molecular chain structure [ 111 , 112 ]. Chemical modification methods include terpolymerization, capping, cross linking, chain transfer, block copolymerization and graft copolymerization [ 113 , 114 , 115 ]. Chemical reagents may affect the environmental friendliness of PPC and are therefore not described in this paper.…”