Natural Rubber Soft and sticky,obtained from rubber tree. Long chains can be stretched,but then return to original structure. Chains slide past each other and can be pulled apart easily. Structure is cis-1,4-polyisoprene. Chapter 26 13Chapter 26 13 Natural Rubber • Soft and sticky, obtained from rubber tree. • Long chains can be stretched, but then return to original structure. • Chains slide past each other and can be pulled apart easily. • Structure is cis-1,4-polyisoprene. =>