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Biobased elastomer materials from renewable resources aimed at substitution of petroleum-based derivates for engineering application have recently become a growing research focus. Herein, we brought out the strategy to fabricate elastomer from biobased chemicals—myrcene, itaconic acid, ethanol and nanosilica. Diethyl itaconate, which can be obtained via esterification from itaconate acid and ethanol, was copolymerized with myrcene through a facile method of redox-initiated emulsion polymerization. The copolymers with different diethyl itaconate contents exhibited the number average molecular weight range from 71,000 to 174,000 and predominately composed of 1,4-tans and 1,4-cis myrcene units. The glass transition temperatures of the copolymer were between −17.8 and −46.1 °C. Combing the molecular structure design and silica-silane technology, we manufactured silica/poly(myrcene-co-diethyl itaconate) materials with comparable properties with petroleum based elastomer materials. On the basis of preliminary data, we believe that myrcene-based elastomer is versatile, making an excellent candidate as future elastomer material.

A series of biobased elastomers, poly(di-n-alkyl itaconate-co-isoprene)s (PDAIIs), were prepared by using itaconic acid as a renewable starting material. It is revealed that pendent chain profoundly affected the structure and properties of PDAIIs. The molecular structures of the PDAIIs were analyzed by 1H NMR and FTIR. Dialkyl itaconate to isoprene reactivity ratios measured by Kelen–Tudos method demonstrated that PDAIIs with short side chains tended to alternate copolymerized and the long side chain ones tented to gradient copolymerized. Glass transition temperature, dielectric properties, and thermal stability of the PDAIIs were studied and these properties were tunable by varying the side chain length. Tensile tests revealed that cross-linked PDAIIs are elastic with a high elongation at break. With renewable resources and the side chain adjustability, PDAII elastomers potentially have a positive economic and ecological impact.

Epoxy group-functionalized styrene-butadiene rubbers (G-ESBRs) with different epoxy group contents were synthesized through emulsion polymerization using glycidyl methacrylate (GMA) as the epoxy group-included monomer, and the silica/G-ESBR nanocomposites without silane coupling agents were prepared. The covalent bonding interfaces, resulting from a ring-opening reaction between the hydroxyl groups on the silica surfaces and the epoxy groups of G-ESBR, were formed during the preparation of the silica/G-ESBR nanocomposites. By increasing the epoxy group content, the number of covalent bonds at the interface increases, contributing to an improvement of the interfacial interaction between the G-ESBR and silica and the dispersion of silica, which were verified and analyzed in detail by bound rubber measurement, transmission electron microscopy (TEM) and rubber process analyzer (RPA). The silica/G-ESBR nanocomposites with improved dispersion of silica and interfacial interaction showed decreased rolling resistance and increased wet skid resistance. The mechanical properties of the nanocomposites were greatly improved with increasing epoxy group contents. The highest tensile strength reached 29.4 MPa at a GMA content of 4.8 wt%, a 55.6% increase compared with that of the nanocomposite without epoxy group.

Epoxy group-functionalized biobased elastomer poly(dibutyl itaconate-ter-isoprene-ter-glycidyl methacrylate) (PDBIIG) was synthesized via redox emulsion polymerization using glycidyl methacrylate (GMA) as the epoxy group-included monomer. The silica/PDBIIG nanocomposite was prepared without adding silane coupling agents. The ring-opening reaction, which occurred between the hydroxyl groups on the silica surfaces and the epoxy groups of the PDBIIG chains during mixing and vulcanization, was confirmed via bound rubber tests and Fourier transform infrared spectroscopy. This reaction was facilitated through heat treatment at 150 °C effectively. The introduction of covalent bonds significantly improved the interfacial interaction and dispersion of silica, which was indicated by transmission electron microscopy and rubber process analyzer (RPA) results. With the same silica loading and compounding procedure, the inclusion of 3.7 wt % GMA increased the modulus at 100% strain by 150.0% and the modulus at 300% str...

Bio-based elastomer poly(diethyl itaconate-co-isoprene) (PDEII) was designed and synthesized by redox-initiated emulsion polymerization from diethyl itaconate and isoprene with mass ratio of 20:80, 40:60, 60:40 and 80:20. The number-average molecular weights of PDEII exceeded 140000 with relatively high yields. The physical properties of PDEII, such as glass transition temperatures and thermostability, were comparable with conventional synthetic elastomers and can be readily tuned by varying the ratio of diethyl itaconate to isoprene. The interaction between silica and PDEII macromolecules was effectively enhanced with the increase of diethyl itaconate content by endowing high polarity. The oil-resistance relevant properties of silica/ PDEII80 (80% diethyl itaconate, 20% isoprene) such as retention of tensile strength, retention of elongation at break and change in volume even surpass those of silica/NBR 240S after soaked in ASTM 3# oil at different temperatures.

Highly purified 2,3-butanediol (2,3-BDO) was obtained from glycerol by using metabolically engineered Escherichia coli through biosynthetic pathways. The bio-elastomers with high strength and elasticity was then prepared from the synthetic 2,3-butanediol and several commercially renewable monomers as promising materials for engineering applications. The molecular weights, chemical structures, and thermal transitions of the bio-elastomers were confirmed by GPC, NMR, FTIR, TGA, DSC and WAXD. Importantly, the introduction of 2,3-BDO can limit and even prevent the crystallization of these bio-elastomers, which makes them amorphous and ensure their high elasticity. Furthermore, the bio-elastomers were highly reinforced with nanosilica which can meet the requirements for the majority of rubber products. Results of in vitro degradation tests prove these bio-elastomers can adjust the degradation rate of their composites by crosslinking. Cell adhesion and proliferation were adopted to evaluate the potential biocompatibility of SiO2/PBPSSI composites and the results indicated that all the SiO2/PBPSSI composites were essentially noncytotoxic. In general, the petroleum-independent monomers, relatively simple synthesis and adjustable degradation rate could greatly reduce environmental impact and the fine mechanical properties and excellent biocompatibility make these novel synthetic bio-elastomers sustainable materials for engineering applications.

Three ullazine-based organic sensitizers (QD1, QD2 and QD3) have been designed, synthesized, and characterized for dye-sensitized solar cells (DSSCs). Ullazine possesses some attractive properties, such as a planar π-system to promote intensely the intramolecular charge transfer (ICT) between ullazine donor units and cyanoacrylic acid or carboxylic acid acceptor units. The tuning of π-spacers and anchoring groups led to variation of the photovoltaic performances. The DSSC based on QD1 with a cyanoacrylic acid and ethylene, obtained a PCE of 5.28%, which was higher than that of QD2 with a carboxylic acid and phenylethylene, and QD3 with a carboxylic acid and thiophene ethylene. The absorption spectra of QD2 and QD3 with the increasing of the length of the π-spacers are blue-shifted compared to that of QD1. The absorbed amount of QD1 was the highest of all, contributing to the highest Jsc of 12.28 mA cm−2. The different Voc values, in the order of QD1 (0.65 V) > QD2 (0.60 V) > QD3 (0.53 V), are caused by the charge recombination rates at the TiO2/dye/electrolyte interface and the electron lifetimes.

Green nanocomposites consisting of bio-based poly(dibutyl itaconate- ter -isoprene- ter -4-vinylpyridine) (PDBIIVP) elastomers with different 4-vinylpyridine (4-VP) contents and natural layered silicate montmorillonite (MMT) were prepared by a green latex co-coagulation method. The effects of the pyridine groups on the interfacial interaction, morphology, and performance of the nanocomposites were investigated. Ionic bonding interfaces, which were confirmed by X-ray photoelectron spectroscopy, were introduced to the nanocomposites through the electrostatic attraction between the protonated pyridine groups of the modified elastomers and the electronegative MMT during the co-coagulation of PDBIIVP latex and MMT aqueous suspension with hydrochloric acid. The dispersion of MMT and the interfacial interaction between PDBIIVP and MMT were improved remarkably, as demonstrated by X-ray diffraction, transmission electron microscopy, rubber process analyzer (RPA) results and swelling tests. The mechanical and gas barrier properties of PDBIIVP improved markedly with increasing 4-VP content. For the PDBIIVP with 7.0 wt% 4-VP, the addition of 10 phr of MMT increased the tensile strength by 730% and reduced the gas permeability by 71%.

In this research, crosslinked hybrids of a newly invented bio-based elastomer poly(di-isoamyl itaconate-co-isoprene) (PDII) and 3,9-bis[1,1-dimethyl-2{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl]-2,4,8,10-tetraoxaspiro[5,5]-undecane (AO-80) were designed and prepared by the mechanical kneading of the PDII/AO-80 hybrids at a temperature higher than the melting point of AO-80, followed by the crosslinking of PDII during the subsequent hot-pressing/vulcanization process. The microstructure, morphology, and mechanical properties of the hybrids were systematically investigated in each preparation stage by using DSC, FTIR, XRD, SEM, DMTA, and tensile testing. Part of the AO-80 molecules formed an AO-80-rich phase, but most of them dissolved in the PDII to form a very fine dispersion in amorphous form. The results of FTIR and DSC indicated that strong intermolecular interactions were formed between the PDII and the AO-80 molecules. Each PDII/AO-80 crosslinked hybrid showed a single transition with a higher glass transition temperature and significantly higher loss value (tan δ) than the neat PDII because of intermolecular interactions between the PDII and the AO-80 molecules. For instance, tan δ of PDII/AO-80 consisting of 100 phr AO-80 achieved 2.6 times as neat PDII. The PDII/AO-80 crosslinked hybrids with applicability at room temperature are potential bio-based damping materials for the future.

Poly(dibutyl itaconate- co -isoprene- co -methacrylic acid) (PDIM) elastomer was designed and synthesized by redox emulsion polymerization under mild conditions. PDIM has high molecular weight, relatively high yield, and low glass transition temperature ( T g). The structure of PDIM was determined by FTIR and NMR, and the carboxyl content was obtained by titration in a non-proton solvent. Tensile strength and elongation at break increased with increasing carboxyl content. In addition, the interaction between PDIM and silica was elucidated by rubber process analyzer (RPA) and TEM, and the results showed that the silica-PDIM interaction was strong, but the silica-silica interaction was weak.

Bio-based poly(dibutyl itaconate-ter-isoprene-ter-4-vinylpyridine) (PDBIIVP) elastomers with different 4-vinylpyridine (4-VP) contents were synthesized by redox emulsion polymerization for the purpose of designing and preparing green graphene oxide (GO)/PDBIIVP nanocomposites with strong interfacial interaction. The ionic bonding interfaces in the nanocomposites were the result of electrostatic attraction between the in situ protonated pyridine groups of PDBIIVP and the electronegative GO sheets with hydrochloric acid during latex co-coagulation and were confirmed by X-ray photoelectron spectroscopy. The inclusion of a small amount of 4-VP (less than 7 wt%) improved the dispersion of GO, the interfacial interaction between PDBIIVP and GO, and the performance of the GO/PDBIIVP nanocomposite markedly. The reinforcement effects of GO on the mechanical and gas barrier properties of PDBIIVP increased continuously with increasing 4-VP content. Additionally, GO/PDBIIVP nanocomposites with a fixed 4-VP content and different GO loadings were prepared and characterized. As the GO loading increased, the performance of the nanocomposites improved greatly. For the GO/PDBIIVP with 7.0 wt% of 4-VP and 4 phr of GO, the tensile strength increased by 700%, the volume loss of abrasion decreased by 53%, and the gas permeability decreased by 63% compared with those of the neat PDBIIVP. The remarkable improvements are attributed to the strong ionic bonding interfaces between the pyridine-included bio-based elastomer and GO. We believe that this work of new polymer construction with the functional group targeting the interfacial interaction with GO should be an important strategy for developing GO-based polymer nanocomposites with high performance.

A new dielectric elastomer with large actuated strain driven by low electric field was synthesized from di-n-butyl itaconate and isoprene through free radical redox emulsion polymerization. The effect of the copolymerized proportion of poly(di-n-butyl itaconate-co-isoprene) (PDBII) and the dosage of crosslinking agent on the elastic modulus, dielectric properties, and actuated strain of the elastomer were investigated, and a potential dielectric elastomer candidate containing 70 wt% di-n-butyl itaconate was obtained. The permittivity of the PDBII crosslinked by 3.0 phr of dicumyl peroxide was 5.68 at 103 Hz, which was higher than that of commercial acrylic and silicone dielectric elastomers. Without any prestrain, an actuated strain of 20% was obtained at an electric field of 30 kV mm−1. In order to further increase the actuated strain, barium titanate (BaTiO3), a high-dielectric-constant ceramic powder, was utilized to fill the PDBII to form a BaTiO3/PDBII composite. The dielectric constant of the composite increased with increasing content of BaTiO3, and the elastic modulus of the composite was lower than that of the unfilled PDBII, leading to a larger dielectric actuated strain of the composite.

Novel poly(lactate/butanediol/sebacate/itaconate) (PLBSI) copolyesters with sustainability and biocompatibility were synthesized by using direct melting polycondensation. The molecular weights, chemical structures, and compositions of the copolyesters were confirmed by GPC, NMR, and FTIR. By controlling the content of lactic acid, the copolyesters were transformed from rigid plastics to flexible elastomers. The PLBSI elastomers were highly reinforced with nanosilica which can meet the tensile strength requirements for the majority of rubber products. More importantly, the PLBSI elastomers can be used as PLA tougheners owing to the similar lactate structures of PLA and PLBSI. The toughened PLA can be applied as excellent three-dimensional printing ink. Besides, the crosslinked PLBSI plastics were demonstrated to be promising shape memory polymers with excellent shape fixity and recovery rate. The renewable monomers, relatively simple polymerization, and versatile performance make our PLBSI copolyesters promising for various medical and engineering applications.

A facile method for enhancing the interaction between pristine graphene and nonpolar rubber matrices was developed by preparing a new solution-polymerized styrene-butadiene-p-(2,2,2-triphenylethyl)styrene (TPES) rubber (SBTR). SBTR macroradicals were formed by the thermal decomposition of a 1,1,1,2-tetraphenylethane pendant. The macroradicals were successfully trapped by graphene through the formation of covalent bonds. This was confirmed by rotorless rheometer and X-ray photoelectron spectroscopy measurements. The dispersion of graphene and interfacial interaction between graphene and the SBTR was significantly increased by increasing the TPES content in SBTR composites, as demonstrated by differential scanning calorimetry, scanning electron microscopy, rubber process analysis, and dynamic mechanical thermal analysis. The mechanical properties of the SBTR/GNS composites were significantly improved by the improved dispersion and the increased surface affinity of SBTR for graphene. The developed approach can be generally applied to the functionalization of other polymer matrices by copolymerizing TPES with other vinyl monomers for pristine graphene-based composite materials. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44923.

The gas-barrier properties of elastomer are of particular importance, especially for airtight applications. Poly(di-isoamyl itaconate-co-isoprene) (PDII) is a newly invented and respectable biobased elastomer, but the barrier properties of PDII and its composites with carbon black and silica are not satisfying at all. Because there are abundant ester groups in PDII macromolecules and these groups can contribute to the homogeneous dispersion of layer silicates, we applied layered silicates, including montmorillonite (MMT) and rectorite (REC), into the PDII matrix to improve the air impermeability. MMT/PDII and REC/PDII composites were prepared by a cocoagulation method, and the air impermeability of the PDII elastomer was highly improved. The smallest gas permeability index reached 1.7 × 10−17 m2 Pa−1 s−1 at an REC content of 80 phr; this implied a reduction of 85.5%. A comparison of the two types of silicate/PDII composites showed that the MMT/PDII composites had better properties at low filler contents, whereas the REC/PDII composites had better mechanical and gas-barrier properties at high filler contents. Other structures and properties of the composites were investigated by X-ray diffraction, transmission electron microscopy, and dynamic mechanical rheology. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40682.