Preparation of Biomass-Based Ester End-Capped Hyperbranched Poly(ether)s via Facile One-Pot Reaction and Their Performance as Non-Toxic Plasticizers

Abstract

The aim of this study was to develop a facile one-pot reaction for the synthesis of biomass-based hyperbranched poly(ether)s end-capped as acetate esters (BHE) for use as a sustainable, safe and feasible plasticizer for flexible poly(vinyl chloride) (PVC) materials. BHE is completely miscible with PVC but shows weaker plasticizing effect than dioctyl phthalate (DOP) (E∆Tg value of BHE reaches 64.8%). PVC plasticized with BHE displays greater thermal stability than that of PVC or PVC plasticized with DOP materials. BHE improves the thermal stability and flexibility of PVC materials. As a plasticizer, BHE displays lower solvent extractability and greater volatilization resistance than DOP. Acute oral toxicity indicates that BHE has toxic doses of 5 g/kg, suggesting that BHE is non-toxic.Polymers 2020, 12, 913 2 of 11 exceed 69 mg/kg, which is lower than the amount of DOP that migrates from plasticized polymer products. DOP can migrate from products via volatilization and enter the human body through human respiration [5]. It is estimated that 500,000 pounds of phthalates was released to the environment from US manufacturing facilities in 1997 [6].In order to overcome the toxicity and poor migration resistance of phthalates, a series of alternative plasticizers were prepared. The strategies to prevent plasticizer migration from PVC products mainly include internal plasticized method such as covalently attaching plasticizer onto the PVC matrix [7]; making surface modifications such as gamma irradiation, ultraviolet irradiation and plasma treatment [8]; and adding nanoparticles or ionic liquid [9,10]. These alternative plasticizers include CO 2 -based polycarbonate [11], cardanol-based epoxidized plasticizers [1], epoxidized vegetable oil [12], glycerol/adipic acid hyperbranched poly(ester)s [13], and so on. Glycerol/adipic acid hyperbranched poly(ester)s are thermally stable, are fully compatible with a PVC matrix, provide effective plasticization at acceptable levels, display low migratory potential and do not accelerate degradative dehydrochlorination [13]. However, there are very few reports on the acute oral toxicity of the plasticizers for PVC.Developing bio-based products is highly important because of their low cost, reproducibility and biodegradability [14][15][16]. In this study, we synthesized biomass-based hyperbranched poly(ether)s end-capped as acetate esters (BHE) via a facile one-pot reaction using triethyl citrate as raw material. The obtained BHE, with a larger relative molecular mass and a higher branching degree, is a potential plasticizer that could overcome the shortcoming of the poor migration resistance of lower relative molecular mass plasticizers, such as triethyl citrate and phthalate plasticizers. The plasticization and migration resistance of PVC materials plasticized with BHE were investigated and compared with those of DOP. The plasticizing mechanism was explored with regards to the shift of infrared absorption peaks of ester groups and the generation of hydrogen bonds via fourier transf...

Vanillic Acid as a New Skeleton for Formulating a Biobased Plasticizer

“…PVC materials generally show poor thermal degradation properties due to the presence of structural defects such as tertiary chlorines at branched carbons and chlorine atoms adjacent to internal double bonds. The polar groups in plasticizers can form interactions with the hydrogen (CH–Cl) in PVC chains, and this can stabilize the C–Cl bond, thereby increasing the initial degradation temperature of PVC. ,,− Therefore, we speculate that higher amounts of the plasticizer mean that there are more plasticizer molecules to form interactions with PVC chains, which may increase the initial degradation temperature of the PVC materials.…”

“…Poly­(vinyl chloride) (PVC) is one of the most common thermoplastic commodities and it is used in a wide range of biomedical, construction, food packaging, and wire manufacturing materials due to its low cost and good mechanical properties. − PVC has a hard and brittle nature resulting from the dipole–dipole interactions between macromolecules, while many applications require PVC with excellent flexibility and processability . Therefore, compatible plasticizers that reduce the cohesive dipolar forces among the polymeric chains of PVC are indispensable. − Phthalates have been one of the most commonly used commercial plasticizers for improving the flexibility of PVC. , However, phthalate plasticizers have been found to induce reproductive toxicity in mammals and are suspected endocrine disruptors in humans. , As a result, the usage of phthalates has been regulated and restricted for use in children’s toys and food packaging in some countries. , Furthermore, phthalates are derived from nonrenewable petroleum-based resources and are clearly unsustainable …”

Synthesis of Biomass Based Plasticizer from Linoleic Acid and Cardanol for Preparing Durable PVC Material

“…When PVC blends plasticized with same mass of ELCE and DOP, PVC plasticized with EPAE showed more excellent thermal degradation stability. This is mainly because the epoxy group of ELCE can react with HCl, thereby delaying thermal decomposition [24].…”

Cyanate ester resins with superior dielectric, mechanical, and flame retardance properties obtained by introducing a fluorinated hyperbranched polyaryletherketone

“…[17][18][19] Meanwhile, hyperbranched polymers exhibit higher solubility, lower viscosity, and higher reactivity than linear polymers, which make modified resins present excellent machinability and designability. 20,21 Researchers have developed a variety of hyperbranched polymers with different branched structures and terminal functional groups, such as hyperbranched polyether, [22][23][24] polyester, 25,26 polyimide, 27,28 polysiloxane, 21,29,30 etc. to increase the toughness of the polymer matrix.…”