Identification of LDPE Grades Focusing on Specific CH2 Raman Vibration Modes

Richard Jumeau,François Lahure,Michel Ferriol,Abdesselam Dahoun,Patrice Bourson,Marc Ponçot

doi:10.1155/2013/720598

Abstract

The possibilities of applications of vibrational spectroscopy techniques (Raman spectroscopy) in the analysis and characterization of polymers are more and more used and accurate. In this paper, our purpose is to characterize Low Density Poly(Ethylene) (LDPE) grades by Raman spectroscopy and in particular with CH2 Raman vibration modes. With temperature measurements, we determine different amorphous and crystalline Raman assignments. From these results and on the basis of the evolution of CH2 bending Raman vibration modes, we develop a phenomenological model in correlation with Differential Scanning Calorimetry and in particular with crystalline lamella thickness determination.

Highlights

Nowadays, almost 30% of the plastics world production is dedicated to poly(ethylene) (PE) (77 million tons per year) [1]
In this work, using Raman spectroscopy, a model based on the Low Density PolyEthylene (LDPE) semicrystalline structure and involving the presence of three kinds of CH2 groups in the crystal lamella, has allowed for distinguishing various LDPE grades
Raman spectroscopy proved its efficiency as being very sensitive to weak variations of the environment of the CH chemical bonds

Summary

Introduction

Almost 30% of the plastics world production is dedicated to poly(ethylene) (PE) (77 million tons per year) [1]. This polyolefin is considered as a consumer polymer due to its moderate cost of manufacturing and its physical and mechanical properties compatible with various applications in everyday life. It possesses an excellent electric insulation and shock resistance combined with a very good chemical and biological inertia [2]. For each PE grade corresponds of specific applications, presenting different rheological properties. To be competitive, PE production should be analysed on-line in order to quickly give the main properties of product (Melt Flow Index, additives, flaws, etc.)

Objectives

Results

Conclusion