Inverse Vulcanization Polymer-Modified Eucommia ulmoides Gum with Enhanced Shape Memory Capability and Sound Absorption Property

Abstract

Sulfur-rich polymers (SP) were prepared using styrene as a comonomer in inverse vulcanization with elemental sulfur and used as a vulcanizer for Eucommia ulmoides gum (EUG) modification to generate EUG-SP-x. The effects of SP on the vulcanization process and mechanical properties of EUG-SP-x were investigated. The results showed that the tensile strength and elongation at break increased gradually with the increase of SP from 4 to 8 phr, and EUG-SP-8 displayed a high tensile strength of 29.54 MPa, elongation at break of 573%, and a high toughness of 60.88 MJ m–3, superior to those of conventional vulcanization EUG (EUG-S-5.59 (CB)) and inverse vulcanization NR (NR-SP-8 (CB)). When the amount of SP was 10 phr, the crystallization property of EUG was greatly damaged, and EUG-SP-10 showed the stress–strain curve of elastomers. Dynamic mechanical analysis results showed that tanδ of EUG-SP-8 is 0.3 at −45 °C, 0.111 at 0 °C, and 0.014 at 60 °C, portending excellent low rolling resistance and potential application in green tires. Sound absorption properties and shape memory capabilities were also investigated. EUG-SP-xs displayed improved sound absorption property at room temperature and excellent shape memory capability with quick recovery at moderate temperatures.

Anti-Ultraviolet Biobased Polyesters Synthesized by Acyclic Diene Metathesis Polymerization

“…The mono-olefin monomers used in reverse vulcanization were vinyl compounds with high activity typically and tended to obtain un-crosslinked sulfur copolymers with branched chain structures. 31,33,40 The S−S bond in sulfur copolymers can be thermally activated to form sulfur radicals, which can continue to react with double bonds. Un-cross-linked and cross-linked sulfur copolymers could be obtained by using diolefin monomers, which were affected by the reaction temperature and the type of catalysts.…”

“…In addition, S8 and olefin compounds can polymerize at high temperatures, which is known as reverse vulcanization − that can obtain stable sulfur copolymers. The mono-olefin monomers used in reverse vulcanization were vinyl compounds with high activity typically and tended to obtain un-cross-linked sulfur copolymers with branched chain structures. ,, The S–S bond in sulfur copolymers can be thermally activated to form sulfur radicals, which can continue to react with double bonds. Un-cross-linked and cross-linked sulfur copolymers could be obtained by using diolefin monomers, which were affected by the reaction temperature and the type of catalysts. ,, Typically, the reaction required heating above 160 °C when the S–S bonds began to break and generate the free radicals to initiate polymerization, and the reaction temperature of inverse vulcanization could descend to 130–135 °C by using activator or catalyst. , Among them, Zn­(DTC) 2 has been proven to be a highly efficient activator, and its oleophilic and sulfurphilic moieties make it an ideal phase-transfer catalyst for shuttling reactive sulfur into the organic phase.…”

“…32 Therefore, the polysulfide cross-linking agents provided by inverse vulcanization could be directly applied to the cross-linking of unsaturated polyesters. It has been proven to be used as a cross-linking agent for diene rubbers 31 and Eucommia ulmoides gum, 33 endowing polymers with excellent mechanical properties and recyclability.…”

Step‐growth Polymerization of Aziridines with Elemental Sulfur: Easy Access to Linear Polysulfides and Their Use as Recyclable Adhesives

“…Vinyl comonomers are then polymerized with the generated sulfur radicals to produce cross-linked polysulfide polymers. The resulting inverse vulcanized polymers have found applications in various areas, such as LiÀ S batteries, [9] IR imaging, [10] sound absorption, [11] and sorbents. [12] However, certain limitations in inverse vulcanization still limit the broader applications of the resulting polysulfides.…”

Preparation and Characterization of Body-Temperature-Responsive Thermoset Shape Memory Polyurethane for Medical Applications

“…Shape memory polymers (SMPs) have broad potential applications in aerospace [1], medicine and health [2][3][4], industrial control [5][6][7], surface engineering [8,9], self-healing [10], 3D printing [11][12][13][14][15][16], and other fields [17,18] because they can keep a temporary shape at room temperature and restore to their original shape when stimulated by the outside world [19][20][21][22][23][24]. SMPs are expected to replace traditional shape memory alloys and ceramics (SMAs and SMCs, respectively) in some fields and have become the most intensively studied shape memory materials [25][26][27][28][29][30][31][32][33][34]. Compared with other popular SMPs, such as polyolefin [35] and epoxy resin [36][37][38][39], shape memory polyurethane (SMPU) has wider applications in fields such as biomedicine and smart textiles because of its high degree of deformability, easy processing, adjustable thermal transition temperature, and biocompatibility [40].…”