The unique hydrophilic and antifouling films of poly(thioctic acid)–Fe 3+ hybrid co-networks (PTA–Fe) were successfully prepared by hydration under humid conditions.

The inert carbon-carbon bonds of aromatic systems have long impeded the direct diversification of phenolic feedstocks into value-added scaffolds. Although enzymatic or energy-intensive strategies enable limited arene modifications, the controlled and programmable ring opening of phenols to unlock both skeletal and functional group diversity remains a fundamental challenge. Here we report an operationally simple and efficient nitrogenation strategy for cleaving phenolic arene rings, converting phenols into uniquely structured acyclic N-containing products including cyanopenta-dienoates, cyanopenta-dienamides and cyanopenta-dienoic acids. The method also enables scaffold hopping of corresponding arene rings, leading to important five-, six- and seven-membered N-heterocycles. The strategy demonstrates broad utility in late-stage modification of bioactive molecules, diversified skeletal remodelling of phenolic feedstocks, and the application of ring-opening products in polymer development. This approach transforms phenols into programmable linchpins for accessing underexplored chemical space, offering broad potential for synthetic chemistry and materials science.

Poly(styrene-b-isobutylene-b-styrene) triblock copolymer (SIBS) is an entirely saturated thermoplastic elastomer with an inherent microphase separation due to the thermodynamic incompatibility of hard polystyrene (PS) and soft polyisobutylene (PIB) segments. The mechanical properties are normally improved by increasing the composition of PS and molecular weight of SIBS. The high performance SIBS-based composites with a small amount (<= 0.7 %) graphene oxide-graft-polystyrene (GO-g-wPS) hybrids have been prepared by construction the unique bicontinuous micromorphology and physically cross-linked 3D network. The GO-g-wPS hybrids carrying w-shaped PS chains chemically bonded on GO surfaces could be synthesized by the reaction at water/oil interface and the grafting density (GD) was effectively mediated in the range of 0.06-0.11 mmol g-1 by varying molecular weight (Mn,PS) of PS precursor, reaction temperature and time. The Mn,PS and GD do affect the microphase separation and homogeneous dispersion of GO sheets in the SIBS/GO-g-wPS composites. It is found that the formation of the unique bicontinuous microphase separation morphology can be mainly induced by GO-g-wPS in the composites by keeping SIBS at the same, leading to the great enhancement in mechanical properties even at a very low content of GO-g-wPS. The optimized composite of SIBS with 0.5 % of GO-g0.11-wPS7.6k behaves much higher modulus of 446 MPa, tensile strength of 24 MPa and toughness of 57 MJ m-3 than those (15.7 MPa, 14.0 MPa and 21.9 MJ m-3) of SIBS, respectively. This mechanical tunability offers a useful strategy for developing high-performance nanocomposites with potential applications in biomedical, robotics and energy fields.

Developing semiconductor ceramic materials with lightweight, outstanding stability, and high-performance electromagnetic wave (EMW) absorption are attractive for harsh environments. Due to thermal and chemical stability, designable microstructure, and tunable dielectric property, microstructured silicon carbide (SiC) ceramics offer promising potential as excellent EMW absorbers while limited by the scarce fabricating methods. Here, a simple coaxial electrospinning technology and the high-temperature calcination process are developed for the first time to fabricate hollow SiC microspheres (HSCMs) for EMW absorbers. Owing to the sizeable SiCfree space interface in the shell and internal void, the inner hollow structure also endows HSCMs with excellent EMW absorbing properties. By comparing with the composite of 40 wt% solid SiC microspheres (SSCMs)/paraffine, it is found that the 40 wt% HSCMs/paraffin composite exhibits superior dielectric properties and a minimum reflection loss (RL) value of - 61.6 dB at 7.7 GHz and 3.4 mm thickness, associated with the most considerable adequate absorption bandwidth of 4.9 GHz (from 12.6 to 17.5 GHz) at 1.9 mm thickness. This work gives rise to a handy method for fabricating hollow SiC with lightweight and high-efficiency EMW absorption. It will potentially boost the development of next-generation EMW absorbers for harsh environment applications.

The novel polybutadiene rubbers (CVBR) carrying 88-97% of long cis-1,4 polybutadiene segments (cis-PB, cis-1,4 content >98.3%) and 3-12% of long syndiotactic1,2-polybutadiene segments (sPB, 1,2 content >87.0%) could be successfully synthesized via in-situ coordination polymerizations of butadiene in hexanes in our lab and also be scaled up via continuous polymerization process in pilot (scale: 200 t/a). The natural rubber (NR)-based compound formulations containing different contents of CVBR, and carbon black (CB) fillers were developed and the optimized NR/CVBR/CB vulcanizates with 40% of CVBR were manufactured for the sidewall of all-steel giant offthe-road tire. The storage modulus of NR/CVBR/CB compounds and the elastic modulus, tensile strength and tear strength of NR/CVBR/CB vulcanizates could be remarkably increased by increasing CVBR content. The crack generation and growth could be effectively restricted due to both the fast relaxation, the rigid polymer-filler interface and synergistic effect of high cis-polybutadiene and crystalline 1,2-polybutadiene particles on the strain-induced crystallization behaviors of rubber matrix. The heat build-up of NR/CVBR/CB vulcanizates could be greatly reduced by introduction of cis-PB segments in CVBR for the easy mobility and low hysteresis of macromolecular chains. The NR/CVBR/CB vulcanizates with high strength and elastic modulus, good flex fatigue crack resistance and low heat build-up would meet the requirement for high performance sidewall in manufacturing giant all-steel off-the-road tires.

The piezoresistive sensor assembled by rGO/PSAN composite aerogel is characterized by wide pressure detection range and high sensitivity, and have a broad application prospect in the field of high and low-temperature sensing.

Neodymium-based polybutadiene rubber (Nd-BR) with cis-1,4 content >98.0% was prepared by neodymium carboxylate-based catalyst system and Nd-BR with cis-1,4 content of 94.9% was prepared by neodymium phosphonate-based catalyst system. Commercial products with similar molecular weight (M-n) and molecular weight distribution (M-w/M-n) while different cis-1,4 contents were selected for comparison. The effects of cis-1,4 configuration on properties of Nd-BRs with similar 1,2-configuration content, molecular weight and distribution were investigated. The characteristic stress relaxation time (tau) decreased obviously when the total content of 1,4-configuration (cis-1,4 and trans -1,4) is greater than 99%, and the cis-1,4 content increases from 94.9% to 98.8%, indicating the improvement of processability. The dispersion of carbon black in rubber and bound rubber content of Nd-BR composites were improved as well. The strain-induced crystallization capability was enhanced with the increase of a small amount of cis-1, 4 content, which significantly improved the tensile strength, tear strength, wear resistance, puncture resistance and crack resistance. It is remarked that the rolling resistance and wet-skid resistance were increased with ultra-high cis-1,4 content of more than 98%. Nd-BR with ultrahigh cis-1,4 content of ca. 98.5% and appropriate molecular weight distribution (ca. 2.8) possessed excellent processing properties, mechanical properties and dynamic mechanical properties, which is suitable for the high-performance tires. [GRAPHICS] .

Flexible porous Janus-structured fluorescent nanofibers with efficient white-light emission and excellent hydrophobicity are obtained via a side-by-side electrospinning technique.

Liquid trimethoxy silane-functionalized cis-polybutadiene (cis-PB-Si(OMe)3), possessing number-average molecular weights of cis-PB segments (Mn,PB) ranging from 1800 g/mol to 5400 g/mol, with cis-1,4 content of ca. 80

A series of living cis-polybutadiene (cis-PB) chains with desired molecular weights could be successfully synthesized during the polymerization process at different monomer conversions or by sequential addition of an extra monomer at every polymerization stage. The amphiphilic silicon hydroxyl-functionalized cis-PB (cis-PB-Si(OH)(3)) could be further achieved via copolymerization of the above living cis-PB chains with ethenyltrimethoxy-silane to obtain trimethoxy silane-functionalized cis-PBs and hydrolysis of these polymers. It is found that the star-shaped cis-PBs were formed by self-assembly via hydrogen bonding interaction from the end-functional groups of -Si(OH)(3). The surface of cis-PB-Si(OH)(3) films transformed from hydrophobic to hydrophilic after water induction at 50 degrees C when the M-n of cis-PB segments was lower than 9.1 kg.mol(-1). The above hydrophilic cis-PB-Si(OH)(3) films exhibit good self-healing behavior at 25 degrees C owing to a great contribution from -Si(OH)(3) hydrophilic terminals. The amphiphilic cis-PB-Si(OH)(3) and its aggregates would have potential application in recyclable elastomers or self-healing elastic coatings with low-temperature resistance.

考察了稀土顺丁橡胶BRNd 40和BRNd 60的生胶微观结构、加工性能、混炼胶性能及硫化胶性能,并与国外同类产品NdBR-C-277及NdBR-E-371进行了性能对比.结果表明,稀土顺丁橡胶的顺式-1,4-结构质量分数仅提高2％,即有利于缩短特征应力弛豫时间,改善生胶加工性能和在塑炼过程中的抗剪切降解性能.BRNd 60、BRNd 40与NdBR-C-277及NdBR-E-371均具有优良的混炼加工性能,无机填料在橡胶中的分散效果良好,且前二者炭黑结合胶含量更高.适当加宽分子量分布,也有利于改善炭黑在橡胶中的分散性.BRNd 60、BRNd 40与NdBR-C-277及NdBR-E-371的硫化胶均具有优良的力学性能、动态力学性能、低生热、耐屈挠及耐磨性,且BRNd 60硫化胶的综合性能更佳.

Rare earth polybutadiene with ultra-high mass fraction of cis-1,4-units and different rela-tive molecular mass and narrow molecular weight distribution were prepared, and the continuous pilot industrial enlargement was realized. The effects of relative molecular mass and its distribution,mass fraction of cis-1,4-unit of rare-earth cis-1,4- poly-butadiene rubber on processing properties, physical and mechanical properties and dynamic mechanical properties were studied. The results showed that the number average molecular weight of the prepared rare-earth cis-1, 4- polybutadiene rubber were 1.1×105-3.4 ×105g/mol, and molecular weight distribution were narrow, the mass fraction of cis-1,4-unit were more than 98.0%, even up to 98.5%. When the mass fraction of cis-1,4-unit was more than 98.0%, processing properties, physical and mechanical properties and dynamic mechanical properties were excellent,and were further improved by the narrowing of molecular mass distribution. Also the compression heat and compression perma-nent deformation were reduced.

Effect of SiO2 content on cis-1,4 microstructure content of butadiene (Bd) units, intrinsic viscosity (ND and thermal stability of hybrid materials (PB-Si) were studied, in which SiO2 nanoparticles were covalently attached and pendants along high cis polybutadiene (PB) macromolecular chains Isothermal crystallization characteristics and SiO2 dispersion in PB matrix of PB-Si hybrid and PB/SiO2 blend (PB/Si) with the same SiO2 contents were conducted. The microstructure of Bd units in PB-Si was characterized by Fourier transform infrared spectroscopy (FTIR) and the cis-1,4 content was determined based on the characteristic absorption in FTIR spectrum. The SiO2 content of PB-Si was measured by thermal gravimetric analysis (TGA). The intrinsic viscosity of PB-Si in toluene was tested by Ubbelohde viscometer. Effects of SiO2 content and microstructure (cis-1,4 configuration) on the isothermal crystallization kinetics, crystal morphology and spherulite growth rate of the hybrid materials at low temperatures were investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM) equipped with in situ heating and cooling device. The results show that the intrinsic viscosity and the cis-1,4 contents of Bd units of PB-Si remained almost the same, and thermal stability could be improved with increasing SiO2 content in the materials when SiO2 content was less than 2.5%. For two series of PB-Si-Ni and PB-Si-Nd hybrids, their cis-1,4 contents were determined to be around 96.6% and 98.6% respectively. PB-Si hybrid materials exhibited a much higher crystallization rate compared to PB/Si blends by keeping the cis-1,4 contents and SiO2 content at the same. The crystallization rate increased by introducing a small amount of covalently linked SiO2 nanoparticle pendants along the macromolecular chains The crystallization of PB-Si hybrid materials could be accelerated and the half-crystallization time (t(1/2)) decreased with increasing SiO2 content. PB-Si-Nd hybrid materials with highly linear chains possessed a higher crystallization rate than PB-Si-Ni with short branched chains by keeping cis-1,4 content and SiO2 at the same. The crystallization rate of PB-Si-Nd hybrid materials could be further increased with increasing both SiO2 and cis-1,4 contents. The Avrami exponents (n) for PB-Si hybrid materials with various topological structures were determined to be in the range of 2.0 - 3.0, which indicated a three-dimensional spherulite growth of PB-Si under isothermal condition at low crystallization temperature. The growth rate of spherulites increased with the increase in SiO2 content while keeping other conditions almost the same. The crystallization rate could increase with increased cis-1,4 content, linearity of chain structure and SiO2 content.

The advantages of green tires in energy saving, environmental protection and safety make it become the trend of the tire. Neodymium-based high cis -polybutadiene rubber (Nd-BR) and solution styrene-butadiene rubber (SSBR) are two important raw materials for manufacturing green tire. Situation of green tire, progress in the synthesis of Nd-BR and butadiene-based copolymer, current status of some industrialized Nd-BR and development of rare earth catalysts have been reviewed, which is helpful for the production of high-performance synthetic rubber for green tire. The main Nd-BR producers are Lanxess, Versalis, ChiMei, Kumho, Japan Synthetic Rubber, Nizhnekamskneftekhim, Goodyear, Firestone, Sibur, Synthos and Karbochem. The commercial Nd-BR products are normally divided into three grades according to the various Mooney viscosity (ML1+4100°C) of around 45, 55 and 63. Furthermore, the effect of microstructure, composition and topology on processing property, mechanical properties and dynamic mechanical properties of Nd-BR and butadiene-based copolymer were introduced. Stereo-specificity is a key factor for the performance of Nd-BR product. The results of the characteristic relaxation time ( τ ), yield stress ( T y), 300% modulus ( T 300), and T 300/ T y for various Nd-BR indicated that the increase of cis -1,4 content was benefit for the improvement of processing properties. The decrease of Δ G ʹ with an increase in cis -1,4 content indicated that Nd-BR with high cis -1,4 content of around 98.5% behaved low Payne effect, which was mainly attributed to the strong interaction between polymer and filler. Excellent processing performance means that the addition of fillers to rubber compounds are easy to scatter. These can short the mixing time and produce the highest quality product with the lowest possible cost. Nd-BR products with higher cis -1,4 content possess the superior mechanical properties and dynamic mechanical properties of BR vulcanizates, such as modulus at 300%, tensile strength, abrasion resistance, heat build-up, compression properties and rolling resistance and wet-skid resistance. Nd-BR which possesses cis -1,4 content of more than 98% has more excellent mechanical properties, dynamic mechanical properties, and is suitable for green tire as raw materials for the excellent properties such as low heat build-up, rolling power loss, compression deformation, compression ratio and abrasion loss. Long chain branched Nd-BR possesses an improved cold flow resistance, processing performance and mixing performance with the filler. High cis -1,4 butadiene/styrene elastomer and stereospecfic butadiene/styrene copolymer combine excellent performance of Nd-BR and SBR. Both mechanical performance and skid resistance ability on ice road were increased, while rolling resistance was decreased for the vulcanizates. These excellent properties of the synthetic rubbers are beneficial for manufacture of high-performance green tires.

High cis polybutadienes (cis-PB) with different molecular weights, molecular weight distributions (MWDs) and microstructures have been prepared via coordination polymerization of butadiene with rare earth catalyst system. The commercial cis. PB products (A9712, C9520 and C9634) were also selected for comparison. Isothermal crystallization kinetics and crystal morphology of cis. PB samples were investigated at various temperatures ranging from - 18 degrees C to - 27 degrees C by differential scanning calorimetry (DSC) and polarized optical microscopy (POM) equipped with in situ heating and cooling device, respectively. The Avrami exponent (n) for various cis. PB samples was determined to be in the range of 2. 0 similar to 3. 0, which indicated that the isothermal crystallization of all the cis. PB samples proceeded via three. dimensional spherulite growth. The spherulites with different sizes and shapes could be observed for the cis. PB samples with different molecular weights, MWDs and cis- 1,4 contents. The size of spherulites increased with increasing cis-1,4 contents of cis. PB samples under the same crystallization conditions. The half. crystallization time (t1/2) decreased and the crystallization rate increased with an increase in cis-1,4 content of cis. PB samples by keeping the other conditions almost the same when the cis-1,4 content of cis. PB samples was lower than 98. 4%. However, the crystallization rate decreased with further increasing the cis-1,4 content of cis-PB samples from 98. 4% to around 99. 0%. The crystallization could be greatly accelerated with simultaneous increases in molecular weight and cis-1,4 content of cis-PB samples by keeping the polydispersity almost the same. The crystallization could also be accelerated with narrowing molecular weight distribution of cis-PB samples by keeping the molecular weight and ci-1,4 content almost the same for the cis-PB samples. It was found that the degree of undercooling (Delta T), a driving force for crystallization, increased with increasing the cis-1,4 content of cis-PB samples. The crystallization activation energy (Delta E) was determined to be in the range of - 115 similar to - 140 kJ/mol. The negative values suggest that the crystallization could be accelerated with decreasing temperature. The Delta E values decreased from - 115 kJ/mol to - 130 kJ/mol with increasing the cis. 1,4 content of cis. PB samples from 95. 2% to 98. 2%, indicating that the crystallization rate could be increased more greatly with decreasing temperature for the cis. PB samples with higher cis-1,4 contents when cis. 1,4 contents were lower than 98. 2%. Moreover, the Delta E values kept at around - 137 kJ/mol when the cis. 1,4 content of cis-PB samples was further increased from 98. 2% to 99. 0%, indicating that the dependence of crystallization rate on temperature was similar for the cis-PB samples with more than 98. 2% of cis-1,4 contents.

The homogeneous neodymium-based catalyst systems containing neodymium carboxylate, isobutyl aluminum compound and chlorinating agent were successfully developed for the coordination polymerizations of butadiene, isoprene and styrene in our laboratory. The catalyst possessed high catalytic activity to butadiene polymerization in hexane, leading to an obvious decrease in the dosage of catalyst to low level, e.g Nd/Bd (molar ratio) was around 35 ppm. Simultaneously, the catalyst exhibited high stereo-selectivity to butadiene polymerization in hexane and polybutadienes with extremely high cis-1,4 configuration of around 99% could be produced under appropriate reaction conditions. Based on our interesting fundamental research works, the continuous butadiene polymerizations were conducted to produce high cis-1,4 polybutadiene in pilot scale in SINOPEC. The industrial equipments (capacity: 30 000 t/a) for production of neodymium butadiene rubber (Nd-BR) were successfully built in SINOPEC in 2012 and the innovation technology has been achieved from fundamental research to industrial application for large scale production of Nd-BR. The Nd-BR products are now commercially available with the trade names of BR Nd40, BR Nd50, BR Nd60 with ML (1+4) 100 degrees C of 45 +/- 5, 55 +/- 5, and 63 +/- 5, respectively. The excellent properties of these high cis-1,4 Nd-BR products lead to their especially suitable application in green-tire components.

Stereospecific polymerization of styrene (St) was carried out with a rare earth catalyst system which consisting of rare earth carboxylate (RE), alkyl aluminium (AL) and chlorinating agent (CL). The influences of catalyst systems on polymerization of styrene, kinetics and microstructure of the resulting polystyrene (PS) were investigated. The resulting molecular weight and its distribution, syndiotacticity, crystalline morphology and heat capacity of polystyrene were characterized by GPC,13C NMR, POM and DSC. The results show that styrene polymerization rate was first-order with respect to monomer concentration with RE/AL/chlorinated carboxylic ester (CE) catalyst system, and the apparent propagation activation energy was determined to be 34.4 kJ·mol?1. The multiblock atactic/syndiotactic PS products with high molecular weight (Mn, 2.8×105—6.8×105g·mol?1) and high melting point (Tm,160—260℃) could be obtained using RE/AL/CE. The catalytic activity could be further improved using the mixture of CE with chlorinated hydrocarbon (RX) as chlorinating agent. The apparent propagation rate constants were 3.9, 5.6 and 9.2 times larger than those of RE/AL/CE at 50, 60 and 70℃ respectively. The molecular weight of PS decreased to relatively low molecular weight (Mn, 0.5×104—5.0×105 g·mol?1). The syndiotacticity of PS products was around 60% and their melting points ranged from 170℃ to 240℃.

The random copolymers of glutamic acid (LG) and aspartic acid (ASP), poly(LG-co-ASP), with designed compositions could be successfully synthesized via combination of N-carboxyanhydride ring opening copolymerization with debenzylation. Ring opening copolymerizations of β-benzyl-L-glutamate N-carboxyanhydride (BLG-NCA) and -benzyl-Laspartate N-carboxyanhydride (BLA-NCA) were carried out by using different amines including triethylamine (TEA), diethylamine, n-hexylamine (NHA), triphenylamine, diphenylamine or aniline as initiators. All the 6 amines were highly efficient to get well-defined poly(BLG-co-BLA) copolymers with designed compositions although the polymerizations proceeded via different mechanisms (normal amine mechanism or/and activated monomer mechanism), which are based on chemical structure of amines. The molecular weights of poly(BLG-co-BLA) copolymers could be mediated by both TEA concentration and polymerization time. Then, debenzylation of poly(BLG-co-BLA) copolymers was conducted to prepare the corresponding hydrophilic random copolymers of poly(LG-co-ASP) with α-subunit structure in ASP structural units. The contents of LG structural units in poly(LG-co-ASP) copolymers matched with those of BLG-NCA in NCA-monomer feeds in ring opening copolymerizations initiated by NHA or TEA and were closed to the theoretical line. The diblock copolymer of poly(BLG-b-BLA) could also be synthesized via living NCA ring opening copolymerization by sequential addition of BLGNCA and BLA-NCA.

FTIR spectroscopy in combination with a diamond tipped attenuated total reflectance (ATR) immersion probe was utilized to study in situ the copolymerization of butadiene (Bd) and isoprene (Ip) with neodymium-based catalyst in hexane. The relationship between the signal intensity of monomer and its concentration was investigated. The kinetic study of copolymerization of Bd and Ip was further conducted, and the monomer reactivity ratios were determined via in situ ATR FTIR. The signal band at 1010 cm −1 was assigned to wagging vibration of Bd and its intensity was proportional to Bd concentration ([Bd]) in the range of 0.46–3.88 mol·L −1 . The signal bands at 890 and 989 cm −1 were assigned to wagging vibration of Ip and the signal intensity was also proportional to Ip concentration ([Ip]) in the range of 0.08–4.73 mol·L −1 at 890 cm −1 and 0.08−7.49 mol·L −1 at 989 cm −1 , respectively. Thus the signal band at 1010 cm −1 was chosen to monitor Bd concentration and bands at 989 and 890 cm −1 to monitor Ip concentration during the copolymerization, respectively. It was demonstrated that the conversions of Bd and Ip calculated from FTIR data agreed very well with those obtained gravimetrically. The polymerization rates were first order with respect to both [Bd] and [Ip], respectively at different polymerization temperatures. The apparent propagation activation energy for Bd and Ip could be determined to be 54.4 kJ·mol −1 and 57.7 kJ·mol −1 , respectively. The monomer reactivity ratios were calculated to be 1.08 for Bd ( r Bd ) and 0.48 for IP ( r Ip ) based on FTIR data. The Bd-Ip copolymer products with random sequence could be obtained with only one glass transition temperature.