Novel Intumescent Flame Retardant Masterbatch Prepared through Different Processes and Its Application in EPDM/PP Thermoplastic Elastomer: Thermal Stability, Flame Retardancy, and Mechanical Properties.

Weidi He,Jianbing Guo,Lingtong Li,Xiaolang Chen,Ying Zhou,Meng Wang,Shaopeng Chen,Dengfeng Zhou

doi:10.3390/polym11010050

Abstract

In this work, the ethylene-propylene-diene monomer/polypropylene (EPDM/PP) thermoplastic elastomer filled with intumescent flame retardants (IFR) is fabricated by melting blend. The IFR are constituted with melamine phosphate-pentaerythritol (MP/PER) by compounding and reactive extruding, respectively. The effects of two kinds of MP/PER with different contents on the thermal stability, flame retardancy, and mechanical properties of materials are investigated by Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL-94, cone calorimeter test (CCT), and scanning electron microscopy (SEM). FTIR results show that the reactive extruded MP/PER partly generates melamine pyrophosphate (MPP) compared with compound masterbatches. TGA data indicate that the best thermal stability is achieved when the molar ratio of MP/PER reaches 1.8. All the reactive samples show a higher flame retardancy than compound ones. The CCT results also exhibit the same trend as above in heat release and smoke production rate. The EPDM/PP composites filled with 30 and 35% reactive MP/PER exhibit the improved flame retardancy but become stiffer and more brittle. SEM photos display that better dispersion and smaller particle size are obtained for reactive samples.

Highlights

Thermoplastic elastomer (TPE) is a kind of material combining high elasticity and toughness, and can be processed by the method of thermoplastic base resin [1,2]
The main purpose of this work is to evaluate the effect of melamine phosphate-pentaerythritol (MP/PER) intumescent flame retardants (IFR) system on the ethylene-propylene-diene monomer/polypropylene (EPDM/PP) thermoplastic elastomer and seek to improve the flame retardancy and mechanical properties
thermogravimetric analysis (TGA) results of flame retardant masterbatches show that the value of 1.8 is considered to be the most effective molar ratio of reactive MP/PER

Summary

Introduction

Thermoplastic elastomer (TPE) is a kind of material combining high elasticity and toughness, and can be processed by the method of thermoplastic base resin [1,2]. Compared with traditional rubber materials, the preparing process of TPE has a low energy dissipation and high efficiency, and can be high effectively reclaimed. As one kind of TPE, the ethylene–propylene–diene monomer/polypropylene (EPDM/PP) thermoplastic elastomer is usually prepared by dynamic vulcanization. EPDM is copolymerized by ethylene, propylene and unconjugated diene in which the saturated ethylene and propylene constitutional units in EPDM lead to a nice weather fastness, heat resistance and ozone resistance [7,8,9]. As a plastic component, PP has a relatively high mechanical properties, good resistance of heat, insulativity and fatigue. It is cheap and easy to process [11]

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