4 research outputs found
Covalent Grafting Approach for Improving the Dispersion of Carbon Black in Styrene–Butadiene Rubber Composites by Copolymerizing <i>p</i>‑(2,2′-Diphenylethyl)styrene with a Thermally Decomposed Triphenylethane Pendant
A facile
approach for improving the dispersion of carbon black
(CB) with a few functional groups in a rubber matrix was developed
by preparing a new solution-polymerized styrene–butadiene-<i>p</i>-(2,2′-diphenylethyl)styrene (DPES) rubber (SBDR).
The SBDR was shown to graft onto the surface of the CB through trapping
a polymer radical formed by thermally dissociation of a triphenylethane
pendant. The dispersion of CB in the rubber matrix was markedly improved
by increasing the DPES content in SBDR, as demonstrated by transmission
electron microscopy, small-angle X-ray scattering, and rubber process
analysis. Furthermore, SBDR vulcanizates showed improved mechanical
properties and good dynamic properties for tread rubber with increasing
DPES content. This research provides a universal method for improving
the dispersion of carbon materials containing few functional groups
in polymer matrices
Synthesis of hypergrafted poly[4-(N,N-diphenylamino)methylstyrene] through tandem anionic-radical polymerization of radical-inimer
<p>In this paper, we present a tandem anionic-radical approach for synthesizing hypergrafted polymers. We prepared 4-(N,N-diphenylamino)methylstyrene (DPAMS) as a new radical-based inimer. Linear PDPAMS was prepared through anionic polymerization. Hypergrafted PDPAMS was synthesized through the self-condensing vinyl polymerization of DPAMS with linear PDPAMS. The linear backbone of PDPAMS, which incorporated latent radical initiating sites, served as a ‘hyperlinker’ to link hyperbranched side chains. The molecular weights of hypergrafted polymers increased as the length of the linear backbone chain increased. The hypergrafted structure of the resulting polymer was confirmed using a conventional gel permeation chromatograph apparatus equipped with a multiangle light scattering detector, nuclear magnetic resonance, differential scanning calorimetry, and thermogravimetric analysis. This strategy can be applied to synthesize other complex architectures based on hyperbranched polymers by changing the structure of a polymer backbone through anionic polymerization.</p
Presentation_1_Novel Design of Eco-Friendly Super Elastomer Materials With Optimized Hard Segments Micro-Structure: Toward Next-Generation High-Performance Tires.PDF
<p>Recently, sustainable development has become a significant concern globally, and the energy crisis is one of the top priorities. From the perspective of the industrial application of polymeric materials, rubber tires are critically important in our daily lives. However, the energy consumption of tires can reach 6% of the world's total energy consumption per annum. Meanwhile, it is calculated that around 5% of carbon dioxide comes from the emission of tire rolling due to energy consumption. To overcome these severe energy and environmental challenges, designing and developing a high-performance fuel-saving tire is of paramount significance. Herein, a next-generation, eco-friendly super elastomer material based on macromolecular assembly technology has been fabricated. Hydroxyl-terminated solution-polymerized styrene-butadiene rubber (HTSSBR) with high vinyl contents prepared by anionic polymerization is used as flexible soft segments to obtain excellent wet skid resistance. Furthermore, highly symmetrical 1,5-naphthalene diisocyanate (NDI), different proportions of chain extender, and the cross-linking agent with moderate molecular length are selected as rigid hard segments to achieve simultaneous high heat resistance. Through this approach, a homogeneous network supported by uniformly distributed hard segment nanoparticles is formed because soft segments with equal length are chemically end-linked by the hard segments. This super elastomer material exhibits excellent wear resistance and low rolling resistance. More importantly, the wear resistance, rolling resistance, and wet-skid resistance are reduced by 85.4, 42.3, and 20.8%, respectively, compared to the elastomeric material conventionally used for tire. By taking advantage of this excellent comprehensive service performance, the long-standing challenge of the “magic triangle” plaguing the rubber tire industry for almost 100 years is resolved. It is anticipated that this newly designed and fabricated elastomeric material tailored for tires will become the next generation product, which could exhibit high potential for significantly cutting the fuel consumption and reducing the emission of carbon dioxide.</p
Postsynthetic Lithium Modification of Covalent-Organic Polymers for Enhancing Hydrogen and Carbon Dioxide Storage
Recent experiment and simulation show that introduction
of lithium
in the frameworks can enhance the gas-storage capacities of framework
materials. Here a covalent-organic polymer-1 (COP-1) has been synthesized
through the self-polymerization of monomer 1,3,5-tris((4-bromophenyl)ethynyl)
benzene (TBEB) by the nickel(0)-catalyzed Yamomoto reaction. To enhance
gas adsorption properties of the COP-1 material, we have proposed
a novel lithium-decorating approach in which the alkynyl functionalities
in COP-1 are postsynthetically converted to lithium carboxylate groups
with the aid of dry ultrapure CO<sub>2</sub>. In particular, the H<sub>2</sub> uptake of lithium-modified COP material is 1.67 wt % at <i>T</i> = 77 K and ∼1 bar, which is increased by ∼70.4%,
compared with the unmodified compounds. Besides, the enhancement effects
of lithium modification on CO<sub>2</sub> and CH<sub>4</sub> adsorption
have also been observed. It is expected that this approach proposed
here would provide a new direction for lithium modification of MOFs
and COFs for clean energy and environmental applications