Melt processed elemental sulfur reinforced polyethylene composites

Abstract

Elemental sulfur represents a largely unutilized resource for high performance materials development. In this context, elemental sulfur was investigated as reinforcing agent for high density polyethylene (HDPE) composites via extrusion. We were able to produce homogenous composites with sulfur content up to 30 wt %. Compounding was done at 1908C well above the polymerization temperature of elemental sulfur. Infrared and Raman spectroscopy showed that sulfur did not undergo chemical reaction with HDPE. Additionally, Raman spectroscopy showed that sulfur exists in its most stable allotrope, cyclooctasulfur (S 8 ). Differential scanning calorimetry (DSC) showed that sulfur is present in non-orthorhombic crystal and X-ray diffraction confirms the same. Results suggest that sulfur is predominantly in its cyclooctasulfur allotrope and occupies the amorphous region of HDPE. According to TEM and SEM microscopy, the composites were of high quality, smooth and without distinguishable defects. Quality and smoothness of composites depend on the experimental parameters and sulfur loading. The addition of elemental sulfur significantly improved the elongation at break of the composites from 835 to 1202% (43% increases with 15 wt % sulfur) despite the obvious fact that HDPE possess an already impressive elongation at break quality. Such phenomena have not been reported in the literature. The improved composites would be suitable for a variety of engineering applications. V C 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43060.

Scalable High Refractive Index polystyrene-sulfur nanocomposites via in situ inverse vulcanization

“…Furthermore, faster solidification of sulfur also interfere with the crystalline arrangement of PS chains and reduces the lamellar thickness, hence, increasing in sulfur loading resulted in decreased peak intensity. Similar behaviors was also observed in our previous work when sulfur is blended with high density polyethylene 40 .

Figure 2 XRD of PS, PS-S, PS-SD composites and pure sulfur (insight graph).

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“… 42 N12-S-5 5 260 ± 11.3 45 ± 0.9 945 ± 24 N12-S-10 10 164 ± 10.2 41 ± 0.3 981 ± 4.6 N12-S-20 20 139 ± 13.3 43 ± 1.1 895 ± 5.6 N12-S-30 30 59 ± 17.3 37 ± 2.0 824 ± 21 HDPE-Sulfur 30 932 ± 77 22.25 ± 2.7 638 ± 15 Ref. 40 HDPE-Sulfur- 25 1,048 ± 56 22 ± 2.9 543 ± 40 S-DAS 70 53.62 – 6.1 Ref. 41 S-DIB 35 5.90 ± 0.52 146.23 ± 15 Ref.…”

Rational Sulfur Cathode Design for Lithium–Sulfur Batteries: Sulfur-Embedded Benzoxazine Polymers

“…Because BOP itself did not show this T c peak, we assigned the former peak at 52 °C to the exothermic crystallization of elemental sulfur into monoclinic S 8 , 39 and the latter peak to the melting of longer S−S bonds in the polymer composite and their crystallization (as also observed by Pyun et al 27 ). These results clearly indicate coexistence of both elemental sulfur and linear sulfur chains within S-BOP.…”

A Sulfur Copolymers (SDIB)/Polybenzoxazines (PBz) Polymer Blend for Electrospinning of Nanofibers

“…The abundant amount of excess sulfur coupled with its unique properties has created renewed interest in sulfur as an alternative feedstock for sulfur-based materials [4]. Previous studies were carried out to overcome the challenges of processing elemental sulfur into new materials such as reinforcing filler for composites [5], chemically modified sulfur for sustainable construction material [6], and as feedstock for reacting with another polymer to obtain network structured and soluble sulfur-rich copolymers [7]. However, the processability of sulfur still remains the main challenge for its direct utilization.…”

“…Until recently, polymeric material from direct utilization of sulfur was achieved via a solvent free copolymerization process known as “inverse vulcanization” [1,2]. It is the reversal of established vulcanization process where sulfur served as the backbone of the polymeric material while the carbon aromatic comonomer, 1,3-diisopropenyl benzene (DIB) bind the sulfur chains to form more stable sulfur copolymers (SDIB) [5]. The potential of SDIB as processable polymers with its distinctive properties from the high sulfur content and improved chemical and processing characteristics opened opportunities for more research efforts on potential applications.…”