Multi-omics-driven development of alternative crops for natural rubber production

Natural rubber(NR)is an irreplaceable biopolymer of economic and strategic importance owing to its unique physical and chemical properties.The Parárubber tree(Hevea brasiliensis(Willd.ex A.Juss.)Müll.Arg.)is currently the exclusive commercial source of NR,and it is primarily grown in plantations restricted to the tropical and subtropical areas of Southeast Asia.However,current Parárubber production barely meets the sharply increasing global industrial demand for rubber.Petroleum-based synthetic rubber(SR)has been used to supplement the shortage of NR but its industrial performance is not comparable to that of NR.Thus,there is an urgent need to develop new productive rubber crops with broader environmental adaptability.This review summarizes the current research progress on alternative rubberproducing plants,including horticultural plants(Taraxacum kok-saghyz Rodin and Lactuca L.species),woody plants(Parthenium argentatum A.Gray and Eucommia ulmoides Oliv.),and other plant species with potential for NR production.With an emphasis on the molecular basis of NR biosynthesis revealed by a multi-omics approach,we highlight new integrative strategies and biotechnologies for exploring the mechanism of NR biosynthesis with a broader scope,which may accelerate the breeding and improvement of new rubber crops.

Machine Learning Assisted Design of Natural Rubber Composites with Multi⁃Performance Optimization

Multi⁃performance optimization of tread rubber composites is a key issue of great concern in automotive industry.Traditional experimental design approach via“trial and error”or intuition is ineffective due to mutual inhibition among multiple properties.A“Uniform design⁃Machine learning”strategy for performance prediction and multi⁃performance optimization of tread rubber composites was proposed.The wear resistance,rolling resistance,tensile strength and wet skid resistance were simultaneously optimized.A series of feasible optimization designs were screened via statistical analysis and machine learning analysis,and were experimentally prepared.The verification experiments demonstrate that the optimization design via machine learning analysis meets the optimization requirements of all target performance,especially for Akron abrasion and 60℃tanδ(about 21%and 9%lower than the design targets,respectively)due to the inhibition of mechanical degradation and good dispersion of fillers.

Molecular Structures and Mechanical Properties of Microbe Rapid Coagulation Natural Rubber

In this work,molecular structures,dynamic mechanical properties and glass transition temperatures of microbe coagulated natural rubber（NR） samples were analyzed by using pyrolysis gas chromatography-mass spectrometry（py-GC/MS）,rubber process analyzer（RPA） and dynamic mechanical thermal analysis（DMA）.And the cross-linked network structures and mechanical properties of the corresponding NR vulcanizates were further determined by using nuclear magnetic resonance（NMR） crosslink density spectrometer（XLDS-15） and universal testing machines.The results show that NR raw rubber produced by rapidly coagulated with microorganism exhibits a simple molecular structure composition and good dynamic mechanical properties,and the corresponding NR vulcanizates possess the aggregation structure of high cross-linked density,a high glass transition temperature of-61.5 ℃ and high mechanical properties（tensile strength reaches 25.2 MPa）,as compared with that coagulated with acetic acid.

Preparation and Properties of Rare Earth Modified Carbon Black/Natural Rubber Composites

The oxides Eu, Ho, Er and Dy were used to prepare the hydroxides of rare earth modified carbon black. Then natural rubber latex （NRL） was added into the reactor. The system reacted at 85 ℃ with stirring for 1 h to prepare powdered HAF-Ln（OH）3/NR composites. The effects of the kind and content of Ln on the particle size distribution of P [ NR/HAF-Ln （OH）3 ] and mechanical properties of its vulcanizate were studied respectively. It is found that rare earth can help to get the powder of the composite, the product particle with a diameter less than 0.9mm will be get when the composites containing the compound of Ho, Er and Dy with dosage of 1.0, 1.0, O. 5 percent, respectively. The adding of Ln can improve the tensile strength and tear strength of the vulcanizate effectively, what＇s more, Er and Dy can decrease the permanent set of vulcanizate significantly. The SEM studies shows that P[ NR/HAF-Dy （OH）3 ] vulcanizate shows superior mechanical properties that depend primarily on the absence of free carbon black, the fine dispersion of carbon black in the rubber matrix and better polymer-filler interaction.

Preparation of graphene oxide/natural rubber composites by latex co-coagulation: Relationship between microstructure and reinforcement

Graphene oxide(GO)has recently attracted substantial interest as a possible reinforcing agent for next generation rubber composite materials.In this research,GO was incorporated in natural rubber(NR)composites through latex co-coagulation technique.The microstructures of GO/NR composites were characterized through a combination of transmission electron microscope,scanning electron microscope,X-ray diffraction,Fourier transform infrared spectroscopy,and Differential scanning calorimeter.The results showed that highly exfoliated GO sheets were finely dispersed into NR rubber matrix with strong interface interaction between GO and NR.The mechanical properties of the GO/NR composites were further evaluated.The results showed that the tensile strength,tear strength and modulus can be significantly improved at a content of less than 2 phr.Especially,GO exhibited specific reinforce mechanism in NR due to the stress-induced crystallization effects of NR.The stress transfer from the NR to the GO sheets and the hindrance of GO sheets to the stress-induced crystallization of NR were further displayed in stress-strain behavior of GO/NR composites.These enhanced properties were attributed to the high surface area of GO sheets and highly exfoliated microstructures of GO sheets in NR.

Studies on the Morphology of Natural Rubber/Polyacrylate Interpenetrating Polymer Networks

The interpenetrating polymer network(IPN) systems have attracted a lot of attention because of their unique two-phase structure and properties. There have been many publications concerning the IPNs in which poly (isoprene) (PIP) or polyacrylates (PAC) is formed as one of the networks.In the present study, Four serles of natural rubber(NR)/PAC IPNs were prepared and their morphologies were investigated with dynamic mechanics analysis(DMA) and transmission electron microscopy (TEM).

Preparation and Characterization of Natural Rubber/Silica Nanocomposites using Rule of Similarity in Latex

Rule of similarity and latex compounding techniques were combined for the first time to prepare natural rubber/nanosilica （NR/SiO2） nanocomposite with core-shell nanosilica-poly （methyl methacrylate） （SiO2-PMMA） particles and PMMA-modified natural rubber matrix （NR-PMMA）. The micro- structure of SiO2 and nanocomposites with different SiO2 contents was characterized by fourier transform infrared spectroscopy （FTIR）; the morphology of nanocomposites was investigated with scanning electron microscopy （SEM）; the tensile strength was characterized by tensile testing machine and the thermal stability of composites was studied by thermal gravimetric analysis. Results showed that PMMA chains have successfully grafted onto the surface of SiO2, and the core-shell SiO2-PMMA nanoparticles and NR-PMMA latex have been perfectly incorporated. SiO2-PMMA nanoparticles are evenly distributed over the NR matrix with an average size in the range of 60-100 nm at the low content （SiO2≤ 3 wt%）, while aggregations are apparently observed when 5 wt% SiO2 is loaded. In addition, NP/SiO2 composities possess a considerable improvement in ageing resistance compared with the pure NR. The tensile strength of composite increases from 6.99 to 12.72 MPa, reaching the highest value at a 0.5 wt% SiO2 loading, and then the figure decreases gradually because of the aggregation of SiO2 nanoparticles. It is anticipated that the reported process is to provide a simple and economic way for preparing NR composites.

NANOMECHANICAL MAPPING OF CARBON BLACK REINFORCED NATURAL RUBBER BY ATOMIC FORCE MICROSCOPY

Atomic force microscopy （AFM） has the advantage of obtaining mechanical properties as well as topographic information at the same time. By analyzing force-distance curves measured over two-dimensional area using Hertzian contact mechanics, Young＇s modulus mapping was obtained with nanometer-scale resolution. Furthermore, the sample deformation by the force exerted was also estimated from the force-distance curve analyses. We could thus reconstruct a real topographic image by incorporating apparent topographic image with deformation image. We applied this method to carbon black reinforced natural rubber to obtain Young＇s modulus distribution image together with reconstructed real topographic image. Then we were able to recognize three regions; rubber matrix, carbon black （or bound rubber） and intermediate regions. Though the existence of these regions had been investigated by pulsed nuclear magnetic resonance, this paper would be the first to report on the quantitative evaluation of the interfacial region in real space.

Study on Cerium Oxide Modified Natural Rubber

The action of CeO2powders in natural rubber was studied. The effects of particle size, content and surface modification of CeO2powders on the properties of natural rubber was discussed. The results showed that the scorch and curing time of rubber decreased, the physic mechanical properties and aging resistance of natural rubber vulcanizates enhanced after filled with CeO2powders. Especially tear strength and abrasion resistance increased much, and was raised 25% and 20% respectively. The surface of modified CeO2powders had hydrophobic organize layer which could increase interface cohesion with the rubber and dispersity in rubber resulting in exerting reinforcement effect. The modified CeO2powders improve the physic mechanical properties of rubber much compared with the unmodified CeO2powders.

Determination of Natural Rubber Content in Taraxacum Kok-Saghyz by Pyrolysis Gas Chromatography-Mass Spectrometry

Nowadays,natural rubber(NR)is an indispensable material for industrial production and peoples’daily utilization.The root of Taraxacum kok-saghyz(TKS)contains a large amount of NR,which is potentially to be an alternative rubber source of conventional Hevea brasiliensis(HB).In order to find a convenient,fast and green method for qualitative and quantitative analysis of NR in TKS,a pyrolysis gas chromatography-mass spectrometric(Py-GCMS)method was developed accordingly.The results indicated that the main products of TKS rubber after pyrolysis were isoprene and limonene,respectively,and the limit of detection(LOD)of TKS rubber was 2.603 mg/g.The ratios of NR mass fractions in TKSs by Py-GC-MS ranged from 1.20%±0.20%to 8.61%±0.28%.The developed method has been used for determination of actual TKS samples and can be further applied to the field test for rapid breeding and large-scale cultivation of TKS thereof.

Strategies for Natural Rubber Production and Development in China

The world's natural rubber output was 12. 31 million t and the consumption reached 12. 17 million t in 2015. China's natural rubber output was 0. 85 million t and the consumption reached 4. 724 million t in 2016. Southeast Asian countries are the main natural rubber producing countries,and ITRC policy affects the natural rubber prices. During 2017-2025,the supply of natural rubber in the world is expected to be abundant to meet downstream demand. Based on natural conditions for rubber planting and production costs,China's rubber production should place emphasis on developing ClassⅠrubber production area,strengthening Class Ⅱ rubber production area and adjusting Class Ⅲ rubber production area. It is recommended to build high-output rubber plantations in Class rubber production area in Xishuangbanna; choose rubber farms with good conditions in Class Ⅱ rubber production area and build high-quality rubber production base as the dedicated production raw material base for aviation rubber; expand the Southeast Asia rubber production belt for development of natural rubber industry.

Hybrid Composite Based on Natural Rubber Reinforced with Short Fibers of the Triumfetta cordifolia/Saccharum officinarum L.: Performance Evaluation

This article contributes to the development of the new class of fully biodegradable “green” composites by combining fibers (natural/bio) with biodegradable resin. The vegetable fibers (Triumfetta cordifolia and sugarcane bagasse) treated with NaOH and bleached were incorporated into a natural rubber matrix. The influence of the fiber ratio on the physical properties, tensile strength and surface hardness of the hybrid composites was analyzed. The results show that the addition of fibers in the natural rubber matrix increases the water absorption capacity but gradually reduces it with increasing fiber ratio. The hybrid composites of the NRT50-50B proportions show the best tensile strengths at 20 phr and a shore A hardness of 43.7 at 30 phr. The combination of two fibers has improved the physical and mechanical properties of the hybrid composites which can be used in engineering applications.

Detailed Mechanism and Engineering Applicability of Electrolytic Polymerization Aided by a Magnetic Field in Natural Rubber by Mechanical Approach for Sensing (Part 2): Other and Intrinsic Effects on MCF Rubber Property

The same ordinary electrolytic polymerization of plastic-type polymer solution is applicable to natural rubber, with its C=C bonds, if a magnetic field and a filler are added. With the application of a magnetic field and the magnetic responsive fluid known as magnetic compound fluid (MCF), we have clarified the enhancement of the electrolytic polymerization of NR-latex and the growth of the thickness of vulcanized MCF rubber that results from the addition of a magnetic field. The present new method of MCF rubber vulcanization is effective for use in haptic sensors, which are used widely in various engineering applications. In the previous report, part 1 of this study, we investigated many experimental conditions under mechanical approach for sensing: magnetic field strength;applied voltage;electrodes gap;mass concentration, and the ingredients of the MCF. In the present sequential report, part 2, we investigate many other effects on electrolytic polymerization by the same mechanical approach for sensing as in part 1: the Mullins effect;the Piezo effect;vibration;kind of electrode;atmospheric gas. In particular, we clarify that the voltage generates spontaneously in the MCF rubber and that the MCF rubber becomes a Piezo element. These effects on the electrolytic polymerization as well as the effects of the experimental conditions will be useful in engineering applications. By taking the above-mentioned parameters and effects into account, MCF rubber that is electrolytically polymerized with the aid of a magnetic field, the use of MCF as a filler, and doping, can be useful in haptic sensor applications. In particular, the effectiveness of the Piezo element can be shown.

Detailed Mechanism and Engineering Applicability of Electrolytic Polymerization Aided by a Magnetic Field in Natural Rubber by Mechanical Approach for Sensing (Part 1): The Effect of Experimental Conditions on Electrolytic Polymerization

Ordinary electrolytic polymerization has involved plastic-type polymer solutions. Rubber, especially natural rubber, is one such polymer solution. Rubber has not been focused on until recently due to the fact that electrolytic polymerization has only a very small effect on rubber. However, when we focus on the C=C bonds of natural rubber, the same electrolytic polymerization is applicable to be enlarged on the natural rubber if a magnetic field and a filler are added. With the application of a magnetic field and a magnetic responsive fluid such as magnetic compound fluid (MCF), the effect of electrolytic polymerization on NR-latex such as plastic-type polymer solutions is enhanced, and the thickness of the vulcanized MCF rubber grows in a short time. The present new method of vulcanization of MCF rubber is effective enough that it is widely used in haptic sensors in various engineering applications. In the present report, as mechanical approach for the sensing, by measuring the temperature under electrolytic polymerization, by investigating the electric and dynamic characteristics, and by observing the magnified appearance of the MCF rubber, we clarified the extrinsic effects of many experimental conditions, including magnetic field strength, applied voltage, the electrodes gap, mass concentration, and the ingredients of the MCF. This report is Part 1, to be followed by another sequential report, Part 2, in which other intrinsic effects on the characteristics are dealt with. The experimental conditions used and the results obtained in the present report provide valuable data that will be useful in the making of MCF rubber.

STUDY ON THE PROPERTIES OF BLEND OF NATURAL RUBBER LATEX/METHYL METHACRYLATE GRAFTED RUBBER LATEX BY GAMMA RADIATION

Natural rubber latex （NRL） and methyl methacrylate （MMA） grafted rubber latex were blended in different ratios and irradiated at various absorbed doses by gamma rays from Co-60 source at room temperature. The tensile properties, swelling ratio and permanent set were measured. The maximum tensile strength and modulus at 500% elongation were obtained at an absorbed dose of 8 kGy. Modulus increases from 6.99 MPa to 9.87 MPa for an increase in proportion of MMA grafted rubber from 40% to 60% in the blend at similar absorbed dose. Elongation at break and swelling ratio decrease with increasing absorbed dose as well as the MMA grafted rubber content in the blends. The decreasing trend of permanent set is high up to 5 kGy absorbed dose, and beyond that dose, it becomes almost flat.

Magnetic,thermal stability and dynamic mechanical properties of beta isotactic polypropylene/natural rubber blends reinforced by NiZn ferrite nanoparticles

The dispersion of magnetic nanoparticles in matrix is crucial to ensure optimum performance of the composite.The difficulty level of achieving good dispersion is further increase when a multi-phases of matrix is present.A pre-coating technique of magnetic nanoparticles with polypropylene using ball-mill prior to melt-blending process was employed to prepare a multi-phases thermoplastic natural rubber composite.The effect of filler loading(2 wt%-10 wt%) on morphology,structure,magnetic properties,thermal stability and dynamic mechanical properties of the composites were investigated.It was found that the NiZn ferrite nanoparticles act as nucleating agent to form beta isostatic polypropylene thermoplastic composites.The composites’ magnetic properties are directly dependent on the filler concentration.The dispersion of magnetic fillers in polymer matrix plays role in affecting the magnetic properties and thermal stability.The preference of filler to locate at amorphous phase has distorted the chain orientation of natural rubber and polypropylene.Hence,the polymorphism and crystallinity of the matrix varied as the filler loading increased,affecting the dynamic mechanical properties.It was found that 8 wt% NiZn nanocomposite exhibits highest E’ and tanδ,indicating the dynamic mechanical properties of NiZn nanocomposite are affected by β-phase degree.

Pervaporation Recovery of n-butanol from Its Dilute Solution with Natural Rubber/Styrene-butadiene-styrene Blend Membrane

Natural rubber/styrene-butadiene-styrene(NR/SBS)membrane was prepared by solution blend,and then used for recovery of butanol from its dilute solution by pervaporation(PV).The thermodynamic and mechanical properties of NR/SBS blend membrane were characterized by TGA and tensile test,respectively.A layer of relatively dense blend membrane with the thickness of about 37μm was closely cast on a layer of porous polyvinylidene difluoride(PVDF)support.And there was no obvious phase separation observed between the interface of two layers.Both flux and separation factor increased with increasing feed temperature.Butanol flux increased as feed concentration increased consistently.The blend membrane which got the best performance obtained membrane separation factor of 28.8 with total flux of 2695.2 g/m^(2)h at 70℃ when feed concentration was 4.00wt%.

Novel Approaches of Using of Spirulina Platensis in Natural Rubber Based Composites

The aim of this work was to investigate the influence of Spirulina (Spirulina platensis) as a natural filler on thecuring characterization, morphology and mechanical, thermomechanical and thermal properties of naturalrubber (NR) based composites. Spirulina was introduced into NR mixture in amount of 0 phr, 10 phr and 30 phr.The vulcanization process was carried out at the determined process condition by using hydraulic press atoptimum vulcanization time (t90). It was noticed that Spirulina affected on the reduction of t90, and scorch time(t2) of the NR mixtures. Obtained vulcanizates were subjected to the number of tests e.g. scanning electronmicroscopy analysis, mechanical dynamical analysis, tensile test, hardness, and thermogravimetry. Generally, itwas found that Spirulina added in amount of 10 phr NR positively influenced on tensile strength (TSb), storagemodulus and hardness of obtained composites.

Natural Rubber-Based Ionogels

Natural rubber(NR),besides being an abundant renewable resource for the elastomer industry,can be a potential resource for the design of innovative biobased polymer networks.The present work is based on“telechelic”liquid natural rubber oligomers obtained by controlled chemical degradation of NR.The chain ends of such oligomers can then be functionalized(with acrylate functions in the present case)and reacted with multifunctional crosslinkers in order to form networks.What’s more,the initial solubility of such thermosetting system in an ionic liquid(IL)can be used for the formulation of ionogels.Such solid networks typically containing 80%of IL were produced,resulting in high ionic conductivity performances.The oligomer chain length was shown to affect IL fragility due to confinement and specific interactions of ions with the host polymer network.

Properties of Natural Rubber Biocomposities Filled with Alkaline Modified Oat Straw

Novel elastomer biocomposites based on straw fibers (raw or chemically modified) as reinforcing elements ofnatural rubber (NR) were reported and studied. Oat straw fibres with different average lengths were used.Lignocellulose materials were incorporated into the elastomer, before and after chemical surface modificationinvolving sodium hydroxide. Fourier transform infrared spectroscopy (FTIR) and microscopy techniques wereemployed for characterization of fillers. The kinetics of rubber mixtures, as well as rheometric properties ofcompounds were determined. The cross-linking density was executed on the basis of equilibrium solventswellingmeasurements applying the modified Flory–Rehner equation. The morphology of biocompositessamples was analyzed by a scanning electron microscopy. Mechanical characteristic: the values of hardness,tensile strength and attenuation coefficient were also determined. The physical and chemical investigations haveproved the reinforcing effect of treated oat straw on natural rubber vulcanizates.