Foam extrusion behavior, morphology, and physical foam properties of organic cellulose ester
- PDF / 572,104 Bytes
- 7 Pages / 584.957 x 782.986 pts Page_size
- 87 Downloads / 173 Views
Sven Hendriks Department Extrusion, RWTH Aachen University, Institute of Plastics Processing IKV, 52056 Aachen, Germany
Stephan Kabasci Department Bio-based Plastics, Fraunhofer Institute for Environmental, Safety, and Energy Technology UMSICHT, Osterfelder Straße 3, 46047 Oberhausen, Germany
Hans-Joachim Radusch Department Polymer Technology, Martin Luther University Halle-Wittenberg, Center of Engineering Sciences, 06099 Halle, Germany (Received 1 February 2013; accepted 30 April 2013)
This paper presents recent results of foam extrusion of thermoplastic cellulose acetate (CA) using HFO 1234ze as low global warming blowing agent and talc as nucleating agent. Foam extrusion behavior, physical foam properties, and foam morphologies were studied in detail with respect to blowing agent concentration and talc content. Depending on these parameters, thermoplastic CA exhibits excellent foam extrusion performance with good expansion behavior at the die. Talc as nucleating agent results in homogeneous fine foam morphologies with closed cells [i.e., Fig. 3(3)]. Depending on the blowing agent content and talc content, average cell size ranges from 1 to 0.12 mm and foam density ranges between 100 and 400 kg/m3. I. INTRODUCTION
Polystyrene (PS) is one of the predominant polymers for producing extruded thermoplastic foams for various applications including insulation boards or thermoformed packaging. This polymer is derived from petrochemicals and is nonrenewable. Styrene as the main building block of PS is considered to be toxicologically questionable.1,2 In addition, hydrocarbons such as butane or pentane as well as fluorohydrocarbons such as HFC 134a or HFC 245fa still are the major industrially used blowing agents to produce thermoplastic foams.3–5 The use of renewable resources, the reduction of packaging waste, and the minimization of emissions become more and more important with respect to a more sustainable economy. Traditional foam polymers as well as most of the conventional blowing agents used do not fulfill all of the requirements for sustainability. Consequently, lots of research has been conducted on the use of eco-friendly blowing agents such as inert gases3,6–8 and on foaming bio-based polymers,9–12 for instance thermoplastic starch or poly(lactic acid) (PLA). These biopolymers exhibit several drawbacks with respect to certain foam applications such as trays for hot contents or cushioning products. a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2013.141 2394
J. Mater. Res., Vol. 28, No. 17, Sep 14, 2013
http://journals.cambridge.org
Downloaded: 17 Mar 2015
Poor melt processing and restricted melt properties, embrittlement over time, limited heat distortion resistance for PLA, and insufficient moisture resistance for starch are the main disadvantages. Cellulose acetate (CA) is a bio-based organic cellulose ester. Cellulose as the renewable resource is mainly obtained from wood, cotton linters or recycled paper. Therefore, the use of CA for foaming m
Data Loading...
