Foaming of Vulcanized PP/EPDM Blends Using Chemical Blowing Agents

1992 ◽  
Vol 65 (4) ◽  
pp. 778-791 ◽  
Author(s):  
A. Dutta ◽  
M. Cakmak
Keyword(s):  
Percent Density ◽  
Degree Of Cure ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Density Reduction ◽  
Low Degree ◽  
Foaming Behavior ◽  
Rubber Phase ◽  
Chemical Blowing Agents ◽  
Optimum Balance

Abstract Using two different chemical blowing agents, foaming behavior of partially vulcanized PP/EPDM blends with high EPDM ratio has been studied. The objective was to induce foaming within the EPDM phase prior to complete curing. The results suggest that with proper choice of blowing agent and by optimum balance of curative loading, foams with densities as low as 0.55 g/cm3 could be obtained. This corresponds to nearly 90 percent density reduction which is significantly greater than the 15 to 20% afforded by similar fully-vulcanized dynamically cured blends reported previously. The degree of cure in the rubber phase was determined to play a key role in determining the overall foamability. In particular, the foamability of the blend was found to decrease linearly with increase in the gel content. In addition, the compounding technique also plays a major role in controlling foamability of these blends. Attempts at extrusion foaming of these blends, however, were successful only for blends with a rather low degree of cure.

Study on the Foaming Behavior of PS-CO2 by Using Water or Ethanol as Co-Blowing Agent

2013 ◽  
Vol 748 ◽  
pp. 112-116 ◽  
Author(s):  
Yi Wei Luo ◽  
Chun Ling Xin ◽  
Jiao Sun ◽  
Bao Rui Yan ◽  
Ya Dong He
Keyword(s):  
Cell Size ◽  
Cell Density ◽  
Apparent Density ◽  
Expansion Ratio ◽  
Low Density ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Foaming Behavior ◽  
Low Solubility ◽  
Foam Production

Carbon dioxide (CO2) has been reported as an interesting substitute of banned ozone-depleting blowing agents, such as HCFC and HFC etc., for low-density polystyrene (PS) foam production, but it is difficult to industrialize due to its low solubility in PS matrix; therefore, high pressure is always needed in order to obtain the required gas concentrations for low density foam. Mixtures of blowing agents might be a practical way to make foam processing easy to control. In this paper, the foaming behaviors of PS-CO2 by using water or ethanol as co-blowing agent were investigated. The performances of foams obtained by PS-CO2, PS-CO2-water and PS-CO2-ethanol systems were tested respectively. It was found that cell size increased owing to the existence of co-blowing agent; in particular, the expansion ratio of PS foam obtained by CO2-ethanol was 1.3 times greater than that by CO2. At the same time, cell density as well as apparent density decreased with temperature increasing, while cell size showed the opposite. Cell size and apparent density, rather than cell density, decreased with pressure. These results were explained by the solution behavior of each of blowing agent.

Influences of Modified Chemical Blowing Agents on Foaming of Wood Plastic Composites Prepared from Poly(Vinyl Chloride) and Rice Hull

2011 ◽  
Vol 306-307 ◽  
pp. 869-873 ◽  
Author(s):  
Nawadon Petchwattana ◽  
Sirijutaratana Covavisaruch
Keyword(s):  
Sodium Bicarbonate ◽  
Vinyl Chloride ◽  
Rice Hull ◽  
Wood Plastic Composites ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Maximum Reduction ◽  
Plastic Composites ◽  
Poly Vinyl Chloride ◽  
Chemical Blowing Agents

The influences of the types of chemical blowing agent (CBA) namely endothermic, exothermic and their mixture, on the properties of the foamed poly(vinyl chloride) (PVC) and rice hull wood plastic composites (WPC) were investigated in the current research. Specifically, azodicarbonamide and sodium bicarbonate were selected to represent the exothermic the endothermic CBA respectively. Particles of sodium bicarbonate and azodicarbonamide were modified with 25 wt% citric acid and 20 wt% ZnO respectively, and they were used at 0 to 3.0 wt%. Maximum reduction of density by 45% was achieved when the exothermic CBA was applied at 2.0% by weight. Overall, the flexural properties decreased as the level of the CBA was increased from 0-2.0 wt%, but there was an upturn when the CBA reached 3.0 wt%. The mixture of exo/endothermic CBA illustrated the mechanical properties averaged between their parents.

Foam extrusion of PP-based wood plastic composites with chemical blowing agents and the Celuka technique

2016 ◽  
Vol 53 (6) ◽  
pp. 623-638 ◽  
Author(s):  
Christina Hoffmann ◽  
Marieluise Lang ◽  
Peter Heidemeyer ◽  
Martin Bastian ◽  
Katja Fischer ◽  
...  
Keyword(s):  
Fibre Length ◽  
Base Material ◽  
Wood Plastic Composites ◽  
Blowing Agents ◽  
Foam Extrusion ◽  
Density Reduction ◽  
Plastic Composites ◽  
Twin Screw ◽  
Chemical Blowing Agents ◽  
Wood Content

Wood plastic composites have gained relevance in recent years as an alternative to wood boards. However, because the cavities in wood fibres are compressed by high processing pressure during the extrusion of wood plastic composites, the product densities show a range of up to 1.5 g/cm3 depending on wood content and base material. Particularly in large-sized products, this may be disadvantageous for processors and end users. Foaming of the plastic matrix is a promising approach to reduce the density of wood plastic composites products. This article discusses the foam extrusion of PP-based wood plastic composites with chemical blowing agents in combination with the Celuka technique. Integral wood plastic composites foam with a rigid and plain outer layer was produced using a parallel, counter rotating twin screw extruder. The profiles obtained were analysed with respect to foam structure and mechanical properties. It was possible to achieve a density reduction of up to 0.7 g/cm3 in the foamed wood plastic composites profiles. Furthermore, we demonstrate that wood fibre length and type of chemical blowing agent have a strong effect on the resulting foam morphology.

The Influence of Modifying HDPE on Properties of the Surface

2015 ◽  
Vol 818 ◽  
pp. 101-104 ◽  
Author(s):  
Ľudmila Dulebová ◽  
Tomasz Garbacz ◽  
Volodymyr Krasinskyi ◽  
Branislav Duleba
Keyword(s):  
Physical Properties ◽  
Flow Rate ◽  
Extrusion Process ◽  
Microscopic Structure ◽  
Melt Flow ◽  
Melt Flow Rate ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Chemical Blowing Agents ◽  
Extrusion Product

The aim of the paper was to discover the influence of modifying HDPE with selected agents that is a blowing agent, in the course of the extrusion process, inclusive of determination how the modification affects selected physical properties and properties of the surface of HDPE extrusion product. Endothermic chemical blowing agents in the amount of 0.6 % by mass were used in the research. The article presents selected results of examination of melt flow rate (MFR) and microscopic structure.

Poly(lactic acid) foams reinforced with cellulose micro and nanofibers and foamed by chemical blowing agents

2017 ◽  
Vol 54 (3) ◽  
pp. 577-596 ◽  
Author(s):  
Matheus VG Zimmermann ◽  
Michelle Paola da Silva ◽  
Ademir J Zattera ◽  
Ruth MC Santana
Keyword(s):  
Lactic Acid ◽  
Expansion Method ◽  
Poly Lactic Acid ◽  
Polymeric Foams ◽  
Short Fibers ◽  
Free Expansion ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Chemical Blowing Agents ◽  
Long Fibers

Biodegradable polymeric foams have gained increasing attention as an alternative to conventional polymeric foams, whose recycling is economically unviable due to its low density. Based on this, this article discusses the development of poly(lactic acid) foams produced with the insertion of four and eight parts hundred resin (phr) of long and short cellulose fibers and nanofibers. Short fibers of nanocellulose were obtained by mechanical defibrillation and dried by lyophilization, and long fibers by CO2 supercritical fluid extraction. The poly(lactic acid) foams were produced by adding a chemical blowing agent with a pressure-free expansion method. In general, short fibers of cellulose act as nucleating agents during the expansion of the foam, which is observed by its greater number of smaller-size cells than the non-reinforced poly(lactic acid) foams. The insertion of long fibers of cellulose restricts the mobility of the polymer matrix during the expansion, thus hindering the foam its growth and formation of bubbles.

scholarly journals Effect of Compatibility on the Foaming Behavior of Injection Molded Polypropylene and Polycarbonate Blend Parts

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 300 ◽  
Author(s):  
Bei Su ◽  
Ying-Guo Zhou ◽  
Bin-Bin Dong ◽  
Cao Yan
Keyword(s):  
Morphological Structure ◽  
Potential Method ◽  
Grafted Polymers ◽  
Dynamic Mechanical Analyzer ◽  
Blowing Agent ◽  
Cell Nucleation ◽  
Foaming Behavior ◽  
Thermal Features ◽  
Injection Molded ◽  
Scanning Electron

To improve the foaming behavior of a common linear polypropylene (PP) resin, polycarbonate (PC) was blended with PP, and three different grafted polymers were used as the compatibilizers. The solid and foamed samples of the PP/PC 3:1 blend with different compatibilizers were first fabricated by melt extrusion followed by injection molding (IM) with and without a blowing agent. The mechanical properties, thermal features, morphological structure, and relative rheological characterizations of these samples were studied using a tensile test, dynamic mechanical analyzer (DMA), scanning electron microscope (SEM), and torque rheometer. It can be found from the experimental results that the influence of the compatibility between the PP and PC phases on the foaming behavior of PP/PC blends is substantial. The results suggest that PC coupling with an appropriate compatibilizer is a potential method to improve the foamability of PP resin. The comprehensive effect of PC and a suitable compatibilizer on the foamability of PP can be attributed to two possible mechanisms, i.e., the partial compatibility between phases that facilitates cell nucleation and the improved gas-melt viscosity that helps to form a fine foaming structure.

scholarly journals The influence of blowing agent addition, talc filler content, and injection velocity on selected properties, surface state, and structure of polypropylene injection molded parts

2019 ◽  
Vol 39 (1) ◽  
pp. 3-30 ◽  
Author(s):  
Paweł Palutkiewicz ◽  
Milena Trzaskalska ◽  
Elżbieta Bociąga
Keyword(s):  
Tensile Strength ◽  
Impact Strength ◽  
Filler Content ◽  
Hold Time ◽  
Injection Velocity ◽  
Blowing Agents ◽  
Blowing Agent ◽  
Molded Parts ◽  
Injection Molded ◽  
Injection Cycle

The effects of blowing agent, talc, and injection velocity on properties of polypropylene molded parts were presented. Blowing agent was dosed to plastic in amounts 1–2% and talc 10–20%. The results of selected properties, such as weight, thickness, hardness, impact strength, tensile strength, and gloss, were presented. The article also presents microscopic investigations. The blowing agent and talc content have a large impact on mechanical properties and gloss of parts than addition of blowing agent. The use of the blowing agent in an amount of 2 wt% will allow the reduce injection cycle time by reducing the hold pressure and hold time. Addition of blowing agents lowers of tensile strength, hardness, impact strength, and significantly affected the gloss. Talc filler contributes to a significant increase in the weight of parts, a decrease in hardness, impact strength, and tensile strength. The injection velocity has no significant effect on parts properties.

Sign in / Sign up

Export Citation Format

Share Document