Low density microcellular foam processing in extrusion using CO<sub>2</sub>

Park, Chul; Behravesh, Amir Hossein; Venter, R. D.

doi:10.1002/pen.10351

Cited by 265 publications

(233 citation statements)

References 18 publications

Supporting

Mentioning

213

Contrasting

Unclassified

Order By: Relevance

“…Foamed polymers are produced using the chemical (CBA) or physical blowing agents (PBA) that provide a gas, which must be dissolved in a polymer, then after decompression it forms nuclei in the polymer matrix which eventually grow into cells [3]. The foaming process allows obtaining a microcellular structure, characterized by a cell size in the range of 0.1-10 lm and cell densities in the range of 10 9 -10 15 cm -3 [4]. Replacement of traditional materials by biodegradable polymers, as well as reducing material costs due to lower weight of final products is an important goal of many research institutes and industry, looking for the cost savings and more sustainable company profile.…”

Section: Introductionmentioning

confidence: 99%

Foaming of Polylactide in the Presence of Chain Extender

Ludwiczak

Kozłowski

2014

J Polym Environ

View full text Add to dashboard Cite

An experimental study on the influence of chain extender (CE) on the properties and foamability of two grades of polylactide (PLA) has been carried out. The influence of CE on the polymer crystallinity and viscoelastic properties that are critical during the foaming process was investigated. After addition of CE an increase in the viscosity and the cold crystallization temperature of PLA was observed. Selection of PLA grade has been correlated with a structure of the polymer. The cellular structure of PLA was obtained during extrusion process using the chemical blowing agent. The addition of 1.0 and 1.5 % CE caused fine cellular structure and low density (0.7 g/dm 3 ) of foamed PLA.

show abstract

Section: Introductionmentioning

confidence: 99%

Foaming of Polylactide in the Presence of Chain Extender

Ludwiczak

Kozłowski

2014

J Polym Environ

View full text Add to dashboard Cite

show abstract

“…It is believed that the poor interface provided channels for gas loss 56 that caused contraction of foams. 53 In other words, when the interface was improved, these channels were reduced, then diffusivity of CO 2 through the composite was decreased, and as a consequence, the amount of lost gas was reduced. 53 Another contributing factor could be that the improved bonding between fibers and plastic prevented easy rupture of cell walls, due to better wetting of plastic on the fibers.…”

Section: Variation Of Foam Densitymentioning

confidence: 98%

“…The melt temperature of the extrudate can be varied by a cooling sleeve to control the expansion ratio. 52,53 Experimental EXPERIMENTAL SETUP Figure 1 shows a schematic of the tandem extrusion system that has been constructed based on the design described above. A twin-screw feeder (AccuRate 3006) with control panel (Danfoss Varispeed A2000) is used to feed a dry-blended mixture of plastic pellets, WF, and additives, at a controlled rate.…”

Section: Designmentioning

confidence: 99%

Development of an extrusion system for producing fine‐celled HDPE/wood‐fiber composite foams using CO₂ as a blowing agent

2004

View full text Add to dashboard Cite

This paper presents an innovative design of a tandem extrusion system for fine-celled foaming of plastic/wood-fiber composites using a physical blowing agent (PBA). The plastic/wood-fiber composites utilize wood-fibers (WF) as a reinforcing filler in the plastic matrix and are known to be advantageous over the neat plastics in terms of the materials cost and some improved mechanical properties such as stiffness and strength. However, these improvements are usually accompanied by sacrifices in the ductility and impact resistance. These shortcomings can be reduced by inducing fine-celled or microcellular foaming in these composites, thereby creating a new class of materials with unique properties. An innovative tandem extrusion system with continuous on-line moisture removal and PBA injection was successfully developed. The foamed composites, produced on the tandem extrusion system, were compared with those produced on a single extruder system, and demonstrated significant improvement in cell morphology, resulting from EXTRUSION SYSTEM FOR PRODUCING FINE-CELLED HDPE/WOOD-FIBER COMPOSITE FOAMSuniform mixing and effective moisture removal. The effects of WF and coupling agent (CA) on the cell morphology were studied. An increase in the WF content had an adverse affect. The cell morphology and foam structures were improved when an appropriate CA was added. C

show abstract

“…Whereas, for the linear PP the cellular structure collapsed due to rupture of the cell walls, a foam with a homogenous cellular structure and significant lower density could be produced using the PP with the high melt strength. Park and coworkers performed intensive studies on the development of extruded PP foams with a very low density and a fine cell structure [2,[5][6][7][8]. Extremely large density reductions up to 90% could be achieved by foaming of a LCB-PP under optimized processing conditions.…”

Section: Introductionmentioning

confidence: 99%

Effect of Long-chain Branching on the Foaming of Polypropylene with Azodicarbonamide

Stange

Münstedt

2006

Journal of Cellular Plastics

View full text Add to dashboard Cite

In this article the influence of long-chain branching on the foaming behavior of polypropylene (PP) is investigated. Different branching contents are achieved by blending a linear PP (L-PP) and a long-chain branched PP (LCB-PP). Whereas, the L-PP does not exhibit any strain hardening in laboratory stretching experiments, blends with amounts of the LCB-PP higher than 2 wt% already show a pronounced strain-hardening behavior. The strain hardening increased with a growing amount of the long-chain branched PP. A laboratory scale foaming apparatus based on a capillary rheometer is developed for the foaming experiments. In foaming tests with azodicarbonamide as chemical blowing agent, a significant improvement of the foaming behavior with respect to a higher expansion ratio, a lower amount of connected cells, and a more homogeneous cell size distribution is found with increasing content of the LCB-PP up to a concentration of 50 wt%. At this concentration, the foaming behavior of the LCB-PP is reached. The results demonstrate that low amounts of long-chain branching can significantly improve the optimal foaming process of PPs with a chemical blowing agent, and that additions of the linear material up to 50 wt% to the LCB-PP do not have any influence on the favorable foaming performance of the long-chain branched PP.

show abstract

Low density microcellular foam processing in extrusion using CO₂

Cited by 265 publications

References 18 publications

Foaming of Polylactide in the Presence of Chain Extender

Foaming of Polylactide in the Presence of Chain Extender

Development of an extrusion system for producing fine‐celled HDPE/wood‐fiber composite foams using CO₂ as a blowing agent

Effect of Long-chain Branching on the Foaming of Polypropylene with Azodicarbonamide

Contact Info

Product

Resources

About

Low density microcellular foam processing in extrusion using CO2

Cited by 265 publications

References 18 publications

Foaming of Polylactide in the Presence of Chain Extender

Foaming of Polylactide in the Presence of Chain Extender

Development of an extrusion system for producing fine‐celled HDPE/wood‐fiber composite foams using CO2 as a blowing agent

Effect of Long-chain Branching on the Foaming of Polypropylene with Azodicarbonamide

Contact Info

Product

Resources

About

Low density microcellular foam processing in extrusion using CO₂

Development of an extrusion system for producing fine‐celled HDPE/wood‐fiber composite foams using CO₂ as a blowing agent