Influence of a novel castor‐oil‐derived additive on the mechanical properties and oxygen diffusivity of polystyrene

Abstract

Mechanical properties, densities, and oxygen diffusion coefficients have been measured in polystyrene samples (PS) as a function of additive loading. The additive employed is based on castor oil, and is a desirable alternative to phthalates. Tensile strength measurements indicate the additive renders PS stronger at low loadings, i.e. it antiplasticizes the material. In contrast, the additive plasticizes PS at high loadings. Specific volumes and oxygen diffusion coefficients do not show this dual behavior. Rather, one observes a monotonic decrease in density and oxygen diffusivity with an increase in additive loading. This suggests that the larger segmental motions responsible for the macroscopic properties of the polymer are influenced by the additive in a different manner than the local motions and confined changes in free volume that govern the mobility of oxygen. These data indicate that antiplasticization cannot be predicted solely from diffusivity and density measurements and, vice versa, trends in diffusivity cannot be deduced from mechanical measurements alone.

Antiplasticization of Polymer Materials: Structural Aspects and Effects on Mechanical and Diffusion-Controlled Properties

“…Researchers have also been attracted by the inherent increase in density brought about by antiplasticization as a possible route for the enhancement of barrier properties for packaging products and protective coatings [28][29][30][31][32].…”

(Meth)acrylate-Free Three-Dimensional Printing of Bio-Derived Photocurable Resins with Terpene- and Itaconic Acid-Derived Poly(ester-thioether)s

“…Synthesized poly­(ester-thioether)­s were mixed with the bifunctional cross-linker I 2 B 1 , plasticizer 9-hydroxystearic acid monoglyceride triacetate (Grindsted Soft-N-Safe; SNS), radical photoinitiator ethyl phenyl­(2,4,6-trimethylbenzoyl)­phosphinate (Et-APO), polymerization inhibitor 2,6-di- tert -butyl-4-methylphenol (BHT), and photosensitizer 2-isopropylthioxanthone (ITX) according to the proportions reported in Figure to obtain a methacrylate-free liquid resin that can harden when exposed to radiation ranging between 380 and 420 nm, covering the nominal spectral range emitted by the screen of 3D printers. In fact, the FTIR spectrum of the selected photoinitiator exhibits an absorption peak centered at 370 nm and spreading up to 410 nm, and the photosensitizer ITX is characterized by light absorption between 380 and 415 nm. , SNS, mainly composed of 9-hydroxystearic acid monoglyceride triacetate, was selected as a plasticizer because it can be obtained from naturally occurring castor oil and reduce the oxygen permeability of the polymer matrix, supporting the photopolymerization process by reducing the concentration of radical-inhibiting oxygen triplet species . Moreover, test prints performed without the addition of any plasticizers formed brittle materials that broke as the cured material was detached from the build plate.…”

“… 43 , 44 SNS, mainly composed of 9-hydroxystearic acid monoglyceride triacetate, was selected as a plasticizer because it can be obtained from naturally occurring castor oil and reduce the oxygen permeability of the polymer matrix, supporting the photopolymerization process by reducing the concentration of radical-inhibiting oxygen triplet species. 45 Moreover, test prints performed without the addition of any plasticizers formed brittle materials that broke as the cured material was detached from the build plate. The radical photoinitiator was selected from the family of acyl phosphine oxides, which are characterized by broad absorption bands in the near-UV range up to 420 nm and efficient degradation of their photoexcited states into reactive RS.…”

Characteristics of Self-Healable Copolymers of Styrene and Eugenol Terminated Polyurethane Prepolymer

“…Meanwhile, elongation ability and polymer chain flexibility of materials are significantly increased [38,39]. In recent years, the utilization of eco-friendly modifiers such as epoxidized vegetable oils, biodiesel oils, hydrogenated Castrol oil, citrate esters, and poly (ethylene glycol) of low molecular weight has been investigated [40,41,42].…”