The Clear Idea on the Composition of Natural Rubber

Introduction

Plasticity or viscosity, elasticity, and tensile strength are all characteristics of natural rubber. Natural rubber, on the other hand, is not resistant to oxidation, ozonation, heat, or expansion in oil due to its polar nature and high unsaturated bond concentration in the molecule. To increase the quality of the rubber, engineering is generally done by adding filler with the goal of improving the rubber’s performance. 

Importance of Natural Rubber

Natural rubber is manufactured from latex, a flowing, milky white substance that oozes out of certain plants when they are cut. (Common dandelions, for example, generate latex, which may be seen pouring from their stems when snapped off.) There’s no reason why we couldn’t produce rubber from dandelions in theory, albeit we’d need a lot of them.) Despite the fact that there are over 200 plants that generate latex, almost 99 percent of the world’s natural rubber is made from latex produced by a tree species known as Hevea Brasiliensis, also known as the rubber tree.

Rubber is composed of isoprene polymers with small amounts of other organic compounds as impurities. India rubber, latex, Amazonian rubber, caucho, and caoutchouc are some of the other names for it. The top three rubber producers in the world are Thailand, Malaysia, and Indonesia.

chemical composition of natural rubber

Natural rubber is a polyterpene, which means it’s made up of isoprene molecules twisted together in a twisted chain. Rubber’s very elastic property is due to the cis arrangement of monomer units along the backbone of the carbon chains (see isomer).

Natural rubber comprises roughly 6% non-rubber elements, including 2.2 percent proteins, 3.4 percent lipids (fatty acids), glycolipids and phospholipids, and 0.4 percent carbohydrates, in addition to the hydrocarbon fraction.

Rubber is made up of carbon and hydrogen atoms. Rubber is a polymerized version of isoprene, which has a chemical formula . It is made by chemically processing latex from rubber plants.

 FTIR  of  Natural Rubber Latex Composites

The infrared spectrum of absorption or emission of a solid, liquid, or gas is obtained using the Fourier transform infrared spectroscopy (FTIR) method. An FTIR spectrometer obtains spectral efficiency data over a large spectral range at the same time. This gives it a big advantage more than a dispersive spectrometer, which only measures intensity across a small range of wavelengths at a time.

Fourier Transform Infrared Spectrometry and H Nuclear Electromagnetic Resonance (NMR) spectroscopy were used to determine the microstructures of LNR samples.

In comparison to the NR, the FTIR spectra of LNR samples generated at various pH levels revealed a few additional peaks. For LNR samples generated in acidic media, the wide peak at 3404 cm1, which can be attributed to the asymmetric stretching of the hydroxyl groups of LNR chains, is greatly enlarged.

FTIR spectra of liquid natural rubber (LNR) specimens generated at different pH values of latex.

Advantages of FTIR

Fellgett’s advantage

This is due to the fact that data from all wavelengths is captured at the same time. For observations constrained by a fixed detector noise contribution, it results in a greater signal-to-noise ratio for a given scan duration.

Jacquinot’s Advantage

This is due to the fact that the monochromator in a dispersive instrument contains entry and exit holes that limit the quantity of light that enters through it. Only the diameter of the collimated beam originating from the source determines the interferometer throughput. 

FTIR spectrometers require an aperture to limit the convergence of the collimated beam in the interferometer, even though no slits are required.

Cannes’ advantage

A laser beam of known wavelength travels through the interferometer, calibrating the wavelength scale. This is far more stable and precise than dispersive instruments, which rely on the mechanical movement of diffraction gratings to determine scale. In reality, the accuracy of the interferometer is restricted by the divergence of the beam, which is dependent on the resolution.

Test Method to Find Chemical Compositions of Natural Rubber

The ASTM D297 test techniques are used to conduct a chemical analysis of rubber and determine the chemical composition of natural and manufactured crude rubbers. There are two types of test procedures that are used:

General tests are used to determine the kind and quantity of chemical components in a rubber product, as well as the rubber polymer content (via ASTM D792)

Certain tests – used to determine the presence of specific rubber polymers in a rubber product, such as crude, unvulcanised, recovered, and vulcanised rubbers.

Conclusion

Natural rubber is made from latex, a milky liquid found in latex vessels (ducts) or plant cells. Despite the fact that latex is produced by about 20,000 different kinds of plants, only 2,500 have been recognised as having rubber in their latex.