scholarly journals INFLUENCE OF KRAFT LIGNIN ON THE PROPERTIES OF RUBBER COMPOSITES

Wood Research ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 285-296
Author(s):  
Matshidiso Makhalema ◽  
Percy Hlangothi ◽  
Setumo Victor Motloung ◽  
Lehlohonolo Fortune Koao ◽  
Tshwafo Elias Motaung
Keyword(s):  
Chemical Interaction ◽  
Lignin Content ◽  
Crosslinking Density ◽  
Kraft Lignin ◽  
Rubber Composites ◽  
Practical Applications ◽  
Complex Interactions ◽  
Tensile Tester ◽  
Composite Properties ◽  
Fractured Surface

The influence of lignin content on reclaimed rubber (RR)/natural rubber (NR) blend composite properties has successfully been studied. Scanning electron microscopy (SEM) were used to understand morphology. Fourier-transform infrared spectroscopy (FTIR) for the possible chemical interaction, whereas thermogravimetric analysis (TGA) and tensile tester were used to predict strength and elongation for possible practical applications. The results indicated that the presence of lignin forms cavities which seemed to arise from complex interactions of the blend with the lignin. Those cavities dominated tensile fractured surface and the increase in lignin indicated inconsistencies of interfacial interactions. Lignin RR/NR blend composites revealed a drop in tensile strength and shift in glass transition temperature, except for the highest lignin containing blend composite. More active interactive constituent of the blend appeared to be NR. The interaction has not favored the thermal stability and crosslinking density.

scholarly journals Functionalized Halloysite Nanotubes–Silica Hybrid for Enhanced Curing and Mechanical Properties of Elastomers

Polymers ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 883 ◽  
Author(s):  
Jing Lin ◽  
Dechao Hu ◽  
Yuanfang Luo ◽  
Bangchao Zhong ◽  
Yongjun Chen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Crosslinking Density ◽  
Halloysite Nanotubes ◽  
Styrene Butadiene Rubber ◽  
Positive Contribution ◽  
Butadiene Rubber ◽  
Practical Applications ◽  
Elastomer Composites ◽  
Styrene Butadiene ◽  
Silica Hybrid

Vulcanization and reinforcement are critical factors in governing the ultimate practical applications of elastomer composites. Here we achieved a simultaneous improvement of curing and mechanical properties of elastomer composites by the incorporation of a functionalized halloysite nanotubes–silica hybrid (HS-s-M). Typically, HS-s-M was synthesized by 2-mercapto benzothiazole (M) immobilized on the surface of halloysite nanotubes–silica hybrid (HS). It was found that the HS-s-M uniformly dispersed in the styrene-butadiene rubber (SBR) matrix, offering more opportunity for M molecules to communicate with rubber. In addition, the physical loss of accelerator M from migration and volatilization was efficiently suspended. Therefore, SBR/HS-s-M composites showed a lower curing activation energy and a higher crosslinking density than SBR/HS composites. Moreover, a stronger interfacial interaction between HS-s-M and SBR was formed by the cross-linking reaction, giving a positive contribution to the eventual mechanical properties. The possible vulcanization and reinforcement mechanisms of SBR/HS-s-M composites were also analyzed in detail.

scholarly journals KRAFT LIGNIN AS AN ADDITIVE IN PINE AND EUCALYPTUS PARTICLE COMPOSITION FOR BRIQUETTE PRODUCTION

2019 ◽  
Vol 43 (2) ◽  
Author(s):  
Walter Torezani Neto Boschetti ◽  
Alice do Carmo Precci Lopes ◽  
Robisnéia Adriana Ribeiro ◽  
Rafael Quezada Reyes ◽  
Angélica de Cássia Oliveira Carneiro
Keyword(s):  
Energy Density ◽  
Apparent Density ◽  
Lignin Content ◽  
Chemical Properties ◽  
Calorific Value ◽  
Wood Particle ◽  
Kraft Lignin ◽  
Mechanical Resistance ◽  
Particle Composition ◽  
Eucalyptus Wood

ABSTRACT The objective of this study was to evaluate the properties of briquettes produced with different proportions of pine and eucalyptus wood, as well as to characterize the potential of kraft lignin as an additive in the composition of briquettes for energy generation. The treatments differed from one another in the pine and eucalyptus wood particle ratios (0, 25, 50, 75 and 100%), as well as for the kraft lignin content (0, 2, 4, 6, 8, 10, and 12%). The biomasses were characterized by their physical and chemical properties, and briquette properties were evaluated according to apparent density, lower calorific value (LCV), energy density, and maximum burst load. The results showed an increase in the apparent density as the proportion of lignin and eucalyptus in the briquettes increased. The particle composition of the briquettes had a higher influence on the energy density increase compared to the addition of kraft lignin, being more significant in briquettes produced with higher proportions of eucalyptus. It was also observed that the addition of lignin increased the resistance to the rupture load, and that there was a specific value at which this resistance was higher (at 7% or 11% of lignin, depending on the proportion of particles). Additionally, the briquettes made with 100% pine achieved greater mechanical resistance. In general, kraft lignin presented good potential for use as a briquette additive, contributing to improved energy and mechanical properties.

Role of Adhesion in Viscoelastic Properties of Rubber-Tire Cord Composites

1981 ◽  
Vol 54 (1) ◽  
pp. 72-90 ◽  
Author(s):  
D. C. Prevorsek ◽  
R. K. Sharma
Keyword(s):  
High Frequency ◽  
Viscoelastic Properties ◽  
Optimum Level ◽  
Adhesion Test ◽  
Rubber Composites ◽  
Mechanical Measurements ◽  
Rubber Tire ◽  
Composite Properties

Abstract Dynamic mechanical measurements have been carried out on samples of rubber and PET cord-rubber composites, with and without adhesive, as a function of strain amplitude, temperature, pretension, angle of strain application and time of cycling. The results show that mechanical loss and dynamic modulus depend on these variables as well as the presence and type of adhesive at the cord-rubber interface. Based on these results, we conclude that adhesion plays a significant role in the viscoelastic properties of a composite and it is an important factor along with the properties of components in the analysis of tire performance in terms of composite properties. This study clearly shows that the maximum adhesion may not be the optimum adhesion in tire technology. The most relevant question, i.e., the determination of the optimum level of adhesion for a specific tire, however, remains unanswered. The viscoelastic properties of the composites decrease with time of cycling but the rate of decrease depends upon the level of adhesion in the starting material. This result could be important in the development of a more realistic dynamic adhesion test. Attempts to use the viscoelastic experiments with small amplitude, high frequency strain to determine the onset of fracture in the composite specimen appears to be promising. Work is in progress to determine the potential of this method in the analysis of adhesion.

scholarly journals Self-Sensing Nanocomposites for Structural Applications: Choice Criteria

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 833
Author(s):  
Liberata Guadagno ◽  
Patrizia Lamberti ◽  
Vincenzo Tucci ◽  
Luigi Vertuccio
Keyword(s):  
Direct Consequence ◽  
Crosslinking Density ◽  
Diglycidyl Ether ◽  
Multi Wall Carbon Nanotubes ◽  
Practical Applications ◽  
Bisphenol A Diglycidyl Ether ◽  
Structural Applications ◽  
Service Conditions ◽  
And Storage ◽  
Suitable System

Epoxy resins containing multi-wall carbon nanotubes (MWCNTs) have proven to be suitable for manufacturing promising self-sensing materials to be applied in the automotive and aeronautic sectors. Different parameters concerning morphological and mechanical properties of the hosting matrices have been analyzed to choose the most suitable system for targeted applications. Two different epoxy precursors, the tetrafunctional tetraglycidyl methylene dianiline (TGMDA) and the bifunctional bisphenol A diglycidyl ether (DGEBA) have been considered. Both precursors have been hardened using the same hardener in stoichiometric conditions. The different functionality of the precursor strongly affects the crosslinking density and, as a direct consequence, the electrical and mechanical behavior. The properties exhibited by the two different formulations can be taken into account in order to make the most appropriate choice with respect to the sensing performance. For practical applications, the choice of one formulation rather than another can be performed on the basis of costs, sensitivity, processing conditions, and most of all, mechanical requirements and in-service conditions of the final product. The performed characterization shows that the nanocomposite based on the TGMDA precursor manifests better performance in applications where high values in the glass transition temperature and storage modulus are required.

Viscoelastic Loss Characteristics of Cord-Rubber Composites

1986 ◽  
Vol 14 (2) ◽  
pp. 75-101 ◽  
Author(s):  
F. Tabaddor ◽  
S. K. Clark ◽  
R. N. Dodge ◽  
J. M. Perraut
Keyword(s):  
Complex Form ◽  
Experimental Techniques ◽  
Tire Cord ◽  
Rubber Composites ◽  
Stress Strain ◽  
Complex Moduli ◽  
Composite Moduli ◽  
Tubular Specimens ◽  
Composite Properties ◽  
Rubber Filler

Abstract Calculated and experimentally generated complex moduli of tire cord-rubber composites are compared. Halpin-Tsai equations in complex form are defined and used to calculate the elastic and loss components of the composite moduli. Additionally, stress-strain relationships for bias ply composites are included. Experimental techniques consisted of prestrained cyclic tensile and torsional tests on tubular specimens. Composite properties of typical polyester and steel tire cord reinforcements were evaluated as functions of end count, cross-ply angle, and thickness of rubber filler between plies.

scholarly journals Eucalyptus Kraft Lignin as an Additive Strongly Enhances the Mechanical Resistance of Tree-Leaf Pellets

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 376
Author(s):  
Leonardo Clavijo ◽  
Slobodan Zlatanovic ◽  
Gerd Braun ◽  
Michael Bongards ◽  
Andrés Dieste ◽  
...  
Keyword(s):  
Raw Materials ◽  
Lignin Content ◽  
Physical Stability ◽  
Kraft Lignin ◽  
Raw Material ◽  
Mechanical Resistance ◽  
Pellet Production ◽  
European Standards ◽  
Tree Leaf ◽  
Waste Food

Pelleted biomass has a low, uniform moisture content and can be handled and stored cheaply and safely. Pellets can be made of industrial waste, food waste, agricultural residues, energy crops, and virgin lumber. Despite their many desirable attributes, they cannot compete with fossil fuel sources because the process of densifying the biomass and the price of the raw materials make pellet production costly. Leaves collected from street sweeping are generally discarded in landfills, but they can potentially be valorized as a biofuel if they are pelleted. However, the lignin content in leaves is not high enough to ensure the physical stability of the pellets, so they break easily during storage and transportation. In this study, the use of eucalyptus kraft lignin as an additive in tree-leaf pellet production was studied. Results showed that when 2% lignin is added the abrasion resistance can be increased to an acceptable value. Pellets with added lignin fulfilled all requirements of European standards for certification except for ash content. However, as the raw material has no cost, this method can add value or contribute to financing continued sweeping and is an example of a circular economy scenario.

scholarly journals Hydroxymethylation-Modified Lignin and Its Effectiveness as a Filler in Rubber Composites

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 315 ◽  
Author(s):  
Nor Mohamad Aini ◽  
Nadras Othman ◽  
M. Hussin ◽  
Kannika Sahakaro ◽  
Nabil Hayeemasae
Keyword(s):  
Mechanical Properties ◽  
Nuclear Magnetic Resonance ◽  
Fourier Transform ◽  
Kraft Lignin ◽  
Rubber Matrix ◽  
Rubber Composites ◽  
Rubber Industry ◽  
Compression Set ◽  
Polybutadiene Rubber ◽  
Modified Lignin

Kraft lignin was modified by using hydroxymethylation to enhance the compatibility between rubber based on a blend of natural rubber/polybutadiene rubber (NR/BR) and lignin. To confirm this modification, the resultant hydroxymethylated kraft lignin (HMKL) was characterized using Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) spectroscopy. It was then incorporated into rubber composites and compared with unmodified rubber. All rubber composites were investigated in terms of rheology, mechanical properties, aging, thermal properties, and morphology. The results show that the HMKL influenced the mechanical properties (tensile properties, hardness, and compression set) of NR/BR composites compared to unmodified lignin. Further evidence also revealed better dispersion and good interaction between the HMKL and the rubber matrix. Based on its performance in NR/BR composites, hydroxymethylated lignin can be used as a filler in the rubber industry.

scholarly journals Lignin Phenol Formaldehyde Resoles Using Base-Catalysed Depolymerized Kraft Lignin

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1162 ◽  
Author(s):  
Pia Solt ◽  
Björn Rößiger ◽  
Johannes Konnerth ◽  
Hendrikus van Herwijnen
Keyword(s):  
Phenol Formaldehyde ◽  
Lignin Content ◽  
Building Blocks ◽  
Kraft Lignin ◽  
Phenol Content ◽  
Adhesive Properties ◽  
Phenolic Resins ◽  
Adhesive Bonds ◽  
Phenolic Components ◽  
Softwood Kraft Lignin

Lignin phenol formaldehyde (LPF) resols were produced using depolymerized lignin fractions at various levels of phenol substitution (50 to 70 wt %). To produce monomeric-rich (BCD-oil) and oligomeric (BCD-oligomers) bio-based phenolic compounds, softwood kraft lignin was base-catalysed degraded. These base-catalysed depolymerized (BCD) building blocks were further used to substitute phenol in the synthesis of phenolic resins and were characterized in detail (such as viscosity, free formaldehyde and phenol content, chemical composition, curing and bonding behaviour). The adhesive properties were compared to a phenol formaldehyde (PF) reference resin and a LPF with untreated kraft lignin. The resins synthesized with the two depolymerized lignin types differ significantly from each other with increasing phenol substitution. While with LPF-BCD-oligomers the viscosity increases and the bonding strength is not effected by increasing lignin content in the resin, a reduction of these properties could be observed with LPF-BCD-oil. Furthermore, LPF-BCD-oil showed similar curing behaviour and ultimate strength as the reference LPF. Adhesive bonds made using LPF-BCD-oligomers exhibited similar strength to those made using PF. Compared to the reference resins, it has been demonstrated that modified renewable lignin based phenolic components can be an equally performing alternative to phenol even for high degrees of substitution of 70%.

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