Comparison Study Between Extrusion and Injection Molding on Cellular Structure of Pp/Ps/Pmma Ternary Blend Foam

Abstract

The effect of blending method on the blend morphology as well as cellular structure of Polypropylene (PP)/Polystyrene (PS)/ Polymethyl methacrylate (PMMA) ternary polymer blend was investigated. The blending method highly influenced the dispersion and size of dispersed domain where the injection molding method was successfully reduced the size of dispersed domain from 10 µm by extrusion further down to 1 µm in average diameter. The batch pressure quenched foaming of the ternary blend prepared by extrusion and injection molding with supercritical carbon dioxide (CO 2 ) was conducted in the temperature range of 130 to 160°C to observe the controllability of bubble location and size in two different ternary blend systems. The experimental results showed that method of sample preparation is one of the important factors in controlling the cellular structure of ternary blend foam besides interfacial tension, foaming temperature, and viscoelasticity.Keywords: polymer blend, extrusion, injection molding, cellular structure, foam Abstrak Kesan kaedah pencampuran pada morfologi dan juga struktur sel Polipropena (PP)/Polisterina (PS)/ Polimetil metaakrilat (PMMA) campuran pertigaan polimer telah dikaji. Kaedah pencampuran sangat mempengaruhi penyebaran dan saiz domain di mana kaedah pengacuan suntikan telah berjaya mengurangkan saiz domain dari 10 μm oleh kaedah penyemperitan kepada serendah 1 μm diameter purata. Proses pelepasan tekanan secara mendadak dengan karbon dioksida genting lampau (CO 2 ) telah dijalankan bagi penghasilan sampel busar daripada gabungan pertigaan polimer dalam lingkungan suhu 60-130°C untuk melihat kebolehkawalan lokasi gelembung dan saiz. Keputusan eksperimen menunjukkan bahawa kaedah penyediaan sampel, tegangan antara permukaan dua polimer, suhu pembentukan busar dan likat-kenyal adalah faktor penting untuk mengawal struktur sel dalam sistem gabungan pertigaan polimer.Kata kunci: percampuran polimer, penyemperitan, pengacuan suntikan, struktur sel, busar ISSN -2506 Rahida Wati & Ohshima: COMPARISON STUDY BETWEEN EXTRUSION AND INJECTION MOLDING ON CELLULAR STRUCTURE OF PP/PS/PMMA TERNARY BLEND FOAM 128Introduction Polymer blends received many attentions due to the increasing application of plastic industry especially in automobile, packing, and many potential applications. Recently, much attention has been directed to ternary polymer blend [1]. Prior to develop a new material based on multi-component polymer, understanding and controlling the phase morphology are the primary interest. This is because the morphology is directly influenced the mechanical performance in polymer blend [2]. These final properties of polymer blend can be controlled by considering polymer molecular structure, composition, molecular weight [3], and method of blend preparation [4]. According to Guo et al. [5], in ternary polymer system, one of the minor components formed an encapsulating layer around domains of other minor components (encapsulation-type morphology) as shown in Figure 1. Whereas in other systems th...