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.

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Monodisperse polymer hemispheres have been fabricated by seed emulsion polymerization of isobutyl methacrylate (iBMA) and acrylic acid (AA) using linear polystyrene (PSt) colloids as seeds, followed by the selected washing of alcohol/water. The morphological investigation performed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicates that polymer colloids are monodisperse round spheres and hemispheres before and after postpolymerization ethanol washing, respectively. Fluorescent microscopy demonstrates that the polymer colloids consist of hydrophobic cores and hydrophilic surfaces. Super-resolution imaging reveals that the thickness of the hydrophilic surface layer in polymer colloids is below 100 nm. The seed emulsion polymerization process was characterized by a fluorescent spectrophotometer and fluorescent microscopy based on the aggregation-induced emission (AIE) mechanism. The fluorescent intensity of AIE-active probes in polymer colloids increases as of emulsion polymerization proceeds. During seed emulsion polymerization, it is observed in the SEM images that polymer colloids are isotropic round spheres. Under a fluorescent microscope, however, one half of each polymer colloid shows much stronger fluorescence than the other half, which indicates that the microphase separation inside each polymer colloid occurs, causing anisotropic distribution of the chemical composition. It is of particular interest that the postpolymerization washing process determines the final shape of the polymer colloids. After the ethanol/water washing process to partially dissolve the hydrophilic polymers, the round polymer colloids are compressed into uniform anisotropic hemispheres as a result of the asymmetric distribution of the chemical composition in polymer colloids, which provides a promising alternative to prepare novel topological polymer colloids.