Difference Between Natural Rubber and Synthetic Rubber

Main Difference – Natural Rubber vs Synthetic Rubber

Natural and synthetic rubbers are two types of polymers with excellent properties that are widely in many industrial and household applications. Each rubber type has its own chemical and physical properties depending on the nature of the monomer and chemical structure of the rubber. The main difference between natural rubber and synthetic rubber is that natural rubber is a natural biosynthesis polymer obtained from a plant called Hevea brasiliensis, whereas synthetic rubbers are man-made polymers under controlled conditions. More differences between these two types of rubbers will be discussed in this article.

This article discusses,

1. What is Natural Rubber?
     – Synthesis, Structure, Properties, Applications

2. What is Synthetic Rubber?
     – Synthesis, Structure, Properties, Examples

3. What is the difference between Natural Rubber and Synthetic Rubber?Difference Between Natural Rubber and Synthetic Rubber - Comparison Summary

What is Natural Rubber

Natural rubber is obtained from a tree called Hevea brasiliensis as an aqueous suspension. It is a natural biosynthesis polymer and is mainly known for its excellent high tensile strength, unlike most of the other polymers. In addition, natural rubber has greater structural regularity, higher green strength and a faster vulcanization rate. Owing to this fast rate of vulcanization, natural rubber has become one of the most important raw materials in many industries including tyres, gloves, rubber carpets, etc. Despite its excellent properties, natural rubber shows very poor resistance to atmospheric oxygen, ozone, oils, and various hydrocarbon solvents. Some more properties of natural rubber include ease of processing, excellent dynamic performance with a low hysteresis loss, good low-temperature properties, ability to bond metal parts, high tear and abrasion resistance, good dynamic performance, low heat buildup during heating and low level of damping.

The monomer of the natural rubber is the cis-1,4-isoprene units. Both latex and dry rubber forms are directly used in many industrial applications. Despite the development of alternative synthetic rubbers with excellent properties, natural rubber still holds 30-40% of market share in world rubber market. Some applications of natural rubber include rubber gaskets, seals, electrical components, hoses and tubes, vibration isolators, drive couplings, shock mounts, etc.

Difference Between Natural Rubber and Synthetic Rubber

Latex being collected from a tapped rubber tree

What is Synthetic Rubber

Synthetic rubbers are the man-made rubbers. The raw materials for the production of synthetic rubbers are mainly obtained as the by-products of crude oil production. Either solution or emulsion polymerization techniques are used to synthesise synthetic rubbers. Unlike natural rubber, the properties of these rubbers can be fabricated according to the final requirement by applying various polymer chemistry techniques. For example, we can develop synthetic rubbers with excellent weather, chemical, temperature and solvent resistance.

There are over 20 difference classes of synthetic rubbers with various chemical and physical properties, which satisfy the ultimate product requirements. Some widely using synthetic rubber types include styrene-butadiene copolymer (SBR), nitrile rubber (NBR), neoprene (CR), ethylene-propylene diene monomer (EPDM), silicon rubber, butyl rubber (IIR) etc. Each rubber has its own unique properties. For example, EPDM is more popular for its weather resistivity, while NBR has the highest oil resistance. Usually, when comparing the properties of synthetic rubber with that of natural rubber, synthetic rubbers are more resistant to oil, certain chemicals, oxygen and ozone, weather and also shows resilience over a wider temperature range.

Main Difference - Natural Rubber vs Synthetic Rubber

EPDM rubber

Difference Between Natural Rubber and Synthetic Rubber

Definition

Natural Rubber: Natural rubber is a natural biosynthetic polymer obtained from a tree called Hevea brasiliensis.

Synthetic Rubber: Synthetic rubber is man-made polymers under controlled conditions.

Synthesis

Natural Rubber: Natural rubber, as the name suggests, naturally occurs in the plant cells.

Synthetic Rubber: Synthetic rubber is synthesised from crude oil by-products by using solution or emulsion polymerization techniques.

Monomer

Natural Rubber: Monomers include cis-1,4-isoprene.

Synthetic Rubber: Monomers are different in each synthetic rubber type.

Polymer Content

Natural Rubber: Polymer content or the quality of the latex vary widely and depends on clone, geographical area, weather, soil type, and non-rubber content of the latex. 

Synthetic Rubber: High-quality rubbers with consistent polymer content can be obtained with very low impurities.

Presence of Antioxidants

Natural Rubber: Antioxidants are naturally present.

Synthetic Rubber: Antioxidants are absent (have to add from outside).

Properties

Natural Rubber: The properties of natural rubber are difficult to change.

Synthetic Rubber: The properties of synthetic rubbers can be adjusted to suit the properties of the final application.

References:

Arayapranee, Wanvimon, and Garry L. Rempel. “Effects of Polarity on the Filler-Rubber Interaction and Properties of Silica Filled Grafted Natural Rubber Composites.” Journal of Polymers 2013 (2013): 1-9. Web.
Höfer, Rainer. Sustainable Solutions for Modern Economies. Cambridge, UK: RSC, 2009. Print.
Whelan, Tony. Polymer Technology Dictionary. London: Chapman & Hall, 1994. Print.
 
Image Courtesy:
“EPDM-Keltan” By Gmhofmann – Own work (CC BY-SA 3.0) via Commons Wikimedia
“Mk’s trip Kannur 2012 DSCN2666″ By Manojk – Own work (CC BY-SA 3.0) via Commons Wikimedia
 

About the Author: Yashoda

Yashoda has been a freelance writer in the field of biology for about four years. He is an expert in conducting research related to polymer chemistry and nano-technology. He holds a B.Sc. (Hons) degree in Applied Science and a Master of Science degree in Industrial Chemistry.