1. SEMINAR PRESENTATION ON MORPHOLOGY OF CRYSTALLINE POLYMERS SUBMITTED TO DEPARTMENT OF CHEMISTRY UNIVERSITY OF LUCKNOW UNDER SUPERVISION OF DR. JOR SARKAR SUBMITTED BY SHAKIR ALI SIDDIQUI M.Sc. Chemistry, Sem- IV ROLL NO.- 180012730055 BATCH:- 2018-19

2. INTRODUCTION Morphology is the science of form and structure. It provides the link between the molecular structure and the bulk properties. As applied to polymers, morphology involves the study of the arrangement of polymer molecules into crystalline and amorphous regions. Polymers with higher crystallinity are denser, stiffer, harder, tougher and more resistant to solvents. Amorphous domains add flexibility and promote ease of processing below the melting temperature.

3. AMORPHOUS PVC GPPS PMMA ABSCRYSTALLINE PE, HDPE, LDPE, etc. PP PA POLYESTERS POM PTFE

4. STEREOCHEMISTRY OF THE POLYMERS Double bonds in the polymer chain can show cis- or trans- isomerism. Due to the geometrical isomerism Gutta percha allows crystallization while natural rubber does not.

7. DEGREE OF CRYSTALLINITY No polymer is 100% crystalline in nature, it may either be 100% amorphous or semicrystalline. The fraction of polymer which is crystalline in nature is termed degree of crystallinity. The degree of crystallinity may be defined as the ratio of mass of the crystalline portion of the sample to the total mass.

8. CRYSTAL STRUCTURE OF THE POLYMERS Polymers are conventionally classified as crystalline and amorphous. Many polymers give sharp and diffuse, both types of features, when studied under X-rays i.e. they are semi crystalline in nature.

9. THE UNIT CELL OF CRYSTALLINE POLYMERS

10. THE FRINGED MICELLE MODEL According to fringed micelle model, the crystallites are about 1000 nm long. The disordered regions separating the crystallites are amorphous. The chains are long enough to pass through several crystallites, binding them together.

11. POLYMER SINGLE CRYSTALS The polymer single crystals are the most perfect formations with respect to morphology and structure. The first single crystals of polyethylene were observed by Jaccodine in 1955. Such crystals can be obtained from very diluted (0.01%) solutions of polyethylene in Xylene via slow isothermal crystallization

12. THE CHAIN-FOLDED MODEL Many polymers are crystallized as very thin platelets or lamellae. The chains fold back and forth within an individual plate. Each platelet will consist of a number of polymer molecules.

13. SPHERULITIC MORPHOLOGY Polymers that are crystallized from a melt reveal some interesting microstructures when observed under a polarising microscope. The fig show circular birefringent regions, as seen under a microscope, are called Spherulites.

14. REFERENCES, INTRODUCTION TO PHYSICAL POLYMER SCIENCE L. H. Sperling, INTRODUCTION TO PHYSICAL POLYMER SCIENCE, 4e, 2006. TEXTBOOK OF POLYMER SCIENCE Fred W. Billmeyer, Jr., TEXTBOOK OF POLYMER SCIENCE, 3e, 1984. POLYMER MORPHOLOGY Qipeng Guo, POLYMER MORPHOLOGY, 2016. AN INTRODUCTION TO POLYMER PHYSICS David I. Bower, AN INTRODUCTION TO POLYMER PHYSICS, 2002. FUNDAMEENTALS OF POLYMEER SCIIENCE FOR ENGINEERS Stoyko and Fakirov, FUNDAMEENTALS OF POLYMEER SCIIENCE FOR ENGINEERS, 2017.