Self-assembled lignin-silica hybrid material derived from rice husks as the sustainable reinforcing fillers for natural rubber.

Biomass derived fillers have been developed as sustainable substitution of carbon black (CB) used in rubber industry to reduce the dependence on fossil fuels. Lignin is the abundant component of biomass, but has poor reinforcing performance due to its huge particle size. In this work, we prepared a lignin/silica (LS) hybrid material from rice husks via a facile self-assembly method. The formation of LS cut lignin macromolecules into fragments and resulted in a small average particle size of 320 nm. When LS was filled into the natural rubber to substitute 10 phr CB, both filler-filler interaction and filler-rubber interaction were enhanced compared with the single use of CB. In consequence, the obtained 10LS/40CB/NR vulcanizates showed overall improvement in tensile strength, tear strength and abrasion resistance compared with the 50CB/NR vulcanizates. For the sustainable development of rubber industry, the natural LS hybrid material with low production cost is a promising reinforcing filler for the partial replacement of CB.

Xue B ，Wang X ，Yu L ，Di B ，Chen Z ，Zhu Y ，Liu X ... -  《-》

Turning lignin into treasure: An innovative filler comparable to commercial carbon black for the green development of the rubber industry.

Driven by the global carbon neutrality action, biomass-derived functional materials have been applied in many fields to alleviate the pressure brought by the depletion of fossil energy. However, due to the complex structure, lignin faces many difficulties in its high-value utilization. The second largest biomass in the world has become the largest "natural waste". In this paper, the lignin-based biochar-silica (LB-S) hybrid nanoparticles were prepared via a combination of two-step acid precipitation and carbonization using lignin black liquor extracted from xylose residue and sodium silicate as raw materials. The effects of carbonization temperature and lignin-based biochar (LB) content on the reinforcing properties of LB-S were studied. The results show that the particle size, specific surface area, pore characteristics, and surface polarity of LB-S all affect the mechanical properties of the final vulcanizates. The reinforcement performance of the best sample (LMB500-S) with "high structure" characteristics can be comparable to that of commercial carbon black (CB) N550. This study shows that LMB500-S hybrid nanoparticles with economic benefits possess the potential to completely replace commercial CB, which can turn lignin waste into treasure and promote the green development of traditional rubber industry in the context of carbon neutrality.

He Z ，Li Y ，Liu C ，Yang J ，Qian M ，Zhu Y ，Wang X ... -  《-》

Study on lignin amination for lignin/SiO(2) nano-hybrids towards sustainable natural rubber composites.

Lignin-based hybrid fillers are of increasing importance with regards to the valorization of low-value biomass and the requirement of sustainability in rubber industry, however, a facile lignin modification approach tuning the supramolecular interactions to favor the assembly of the hybrids is in demand. This study aimed to design a lignin/SiO2 nano-hybrid via an in-situ assembly of diethylamine grafted lignin (DL) and SiO2, and investigate its reinforcing effect on natural rubber (NR). DL was prepared through Mannich modification of lignin, and the grafted diethylamine can be clearly identified by FTIR, NMR and elemental analysis. The resultant hybrid (DLSi) displays as homogeneous nanospheres with well integrated DL and SiO2 components as shown in the TEM images, and the hybrid (DLSi1) prepared with weight ratio of DL/SiO2 = 1/2 shows a minimum particle size of 101.8 nm and significantly reduced polarity. Compared to the reference composite filled only with carbon black (CB), NR composites filled with DLSi/CB of 10/40 phr shows comparable mechanical properties and reduced rolling resistance, which is due to the low particle size, homogenous dispersion and strong rubber-filler interfacial affinity. Such remarkable performance suggests that the DLSi hybrid can be a promising versatile biobased filler for the application in gasoline-saving "green" tires.

Qiu J ，Yuan S ，Xiao H ，Liu J ，Shen T ，Tan Z ，Zhuang W ，Ying H ，Li M ，Zhu C ... -  《-》

Converting waste lignin into nano-biochar as a renewable substitute of carbon black for reinforcing styrene-butadiene rubber.

Industrial waste lignin was commonly burnt or discharged into river in the past. However, in this study, lignin has been converted into high value-added nano-biochar as a renewable reinforcing filler of styrene-butadiene rubber (SBR) by a simple high-temperature carbonization treatment. Herein, the physicochemical change in lignin before and after carbonization was investigated. It was found that lignin-derived biochar (LB) consisted of vesicle-like primary nanoparticles which were closely packed to form "high-structure" irregular fragments with a high specific surface area (83.41 m2/g). When incorporating LB into SBR, the tensile properties of LB/SBR composites were significantly improved. At the filler loading of 40 phr, the tensile strength and elongation at break of the rubber composite were improved up to 7.1-folds and 2.4-folds of pristine SBR, respectively. Compared to commercial carbon black (CB) N330, the LB showed a similar reinforcing effect on SBR. However, the analysis on the morphology, stress-strain behavior and dynamic mechanical behavior suggested distinct reinforcing mechanisms for LB- and CB-filled rubber composites, due to the difference in the surface properties and structural characteristic of fillers. This work showed the application potential of LB as a renewable substitute of CB in rubber industry and brought environmental and economic benefits for the disposal of lignin.

Jiang C ，Bo J ，Xiao X ，Zhang S ，Wang Z ，Yan G ，Wu Y ，Wong C ，He H ... -  《-》

Synergistic Effect of Partial Replacement of Carbon Black by Palm Kernel Shell Biochar in Carboxylated Nitrile Butadiene Rubber Composites.

Zainal Abidin Z ，Mamauod SNL ，Romli AZ ，Sarkawi SS ，Zainal NH ... -  《Polymers》