Castor Oil-Based Bioplastics via Polyesterification: Synthesis, Characterization, and Functionalization

Abstract

Synthesis and application of biobased polymers are at the forefront of polymer science. Herein, we report the synthesis, characterization, and functionalization of castor oil-based bioplastics. At first, polymer P1 was synthesized via polyesterification by using monomer 11-bromoundecanoic acid (1) to demonstrate the feasibility of this step-growth polymerization method. The success of this polycondensation technique relies on the high substitution efficiency between terminal groups, carboxylic acid, and carbon-bromide moieties under alkaline conditions. Subsequently, copolymers P2–P5 with varied compositions were obtained by random copolymerization of monomers 1 and 6-bromohexanoic acid (2) in different feed ratios. Linear positive correlation is disclosed between the crystallization (T c) and melting (T m) temperatures of P1–P5 and the molar fraction of 1 within these specimens. Differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) results illustrate good crystallinity of these bioplastics. Furthermore, the degradation of polymers P1–P5 is propelled by an external basic environment while hindered by their intrinsic hydrophobicity, indicating that alkalinity and composition are two essential factors to manipulate the degradation behaviors of biobased polyesters in the bulk state. Ultimately, polymerization of 1 in the presence of 1-pyrenebutyric acid (3), an end-capping agent, was carried out to yield α-pyrene functionalized polymer P7. This material is capable of serving as a practical fluorescent probe and multiwalled carbon nanotube (MWNT) dispersion stabilizer. Polyesterification reported herein represents a facile and cost-effective synthetic strategy and shows great prospects in sustainable polymer materials.

Recyclable, Reprocessable, Anticorrosive, and Hydrolysis-Resistant Long-Chain Aliphatic Polycarbonates as Polyethylene-like Materials

“…TGA curves of these samples show typical two-stage decompositions (Figure S7), corresponding to catastrophic scission of the polymer chain and devolatilization of aromatics/cyclic oligomers, , respectively. It is noticed that the thermal stability of polycarbonate is positively influenced by molecular weight, and this observation is in line with our previous reports. − For example, the superior thermal stability of PC-13 is definitely attributed to its high molecular weight since end groups normally play the role of initiating sites for pyrolysis. In the meantime, PC-13 displays a lower second decomposition stage compared with other specimens, which is best explained as minor cyclic oligomerization for this sample.…”

Recyclable Biomass-Derived Polyethylene-Like Materials as Functional Coatings for Commercial Fabrics: Toward Upcycling of Waste Textiles

“…Our results coincide well with previous reports. 55,56 Figure 4F illustrates the crystallization enthalpies (ΔH c ) of hydrogenated polyesters HP1−HP6, and the values of ΔH c follow the order of HP4 > HP1 > HP5 > HP3 > HP2 > HP6 without any obvious variation trend. On the other hand, as shown in Figures 4C and S22, similar multiple (or broad) peaks are observed on the melting curves of HP1−HP6 regardless of the scanning rate.…”

Synthesis and application of environmental plasticizers based on benzene polyacid ester

“…The temperature corresponding to the peak of the curve between temperature and Tanδ is considered the glass transition temperature (T g ) of the material. 30 T g signifies the temperature at which substances undergo a transition between the glass state and the high elastic state. It is the lowest temperature at which molecular segments can move, determining the upper limit temperature for the use of amorphous thermoplastic plastics.…”