Croydon, United Kingdom
Croydon, United Kingdom

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Zotefoams Plc | Date: 2017-03-29

A process for making a three dimensional foam article of non-uniform shape employs a two-stage nitrogen autoclave process and a pre-form which has a non-uniform cross- section in at least one dimension.

Agency: European Commission | Branch: FP7 | Program: BSG-SME-AG | Phase: SME-2 | Award Amount: 2.55M | Year: 2008

Our concept is to enable the production of high quality foams from engineering grade thermoplastics using existing injection moulding and extrusion equipment installed in our SME communities. We propose the creation of a novel polymer processing technology. We will develop the ability to foam engineering grade thermoplastics without the need for chemical blowing agents or speciality moulding equipment. Our technology offers many advantages for SME injection moulders & extruders in sectors such as aerospace, automotive and construction. We will: Eliminate the need to invest in expensive processing machinery to make foam parts Eliminate the need for chemical blowing agents Reduce material consumption Reduce energy consumption through lower process temperatures Produce low density, consistent foams with excellent mechanical properties Reduce part cost and finishing operation requirements Increase manufacturing flexibility We have selected engineering grade thermoplastics, which will be saturated with nitrogen gas at temperatures above Tg, where diffusion rates of gas within the polymer are significantly increased. The granules will then be cooled below Tg, trapping the nitrogen molecules within. The granules will be packaged and shipped to SME moulders for use in standard moulding machines. During processing, melting of the polymer will release the trapped nitrogen, producing foam in the moulding machine. We will develop our understanding of melt processing technology to ensure optimum processing speed, density and mechanical performance. Initial trials have already indicated the potential of this process but the technology needs considerable further development for successful commercialisation. We strongly believe that our technological breakthroughs will benefit the European polymer processing community, which is facing significant threats from lower cost imports

Izzard V.G.,Kingston University | Izzard V.G.,Zotefoams plc | Bradsell C.H.,Kingston University | Bradsell C.H.,Zotefoams plc | And 7 more authors.
Key Engineering Materials | Year: 2010

It is a fundamental response of any polymeric foam material to undergo non-recoverable deformation following the application of a defined compressive strain, exacerbated by temperature and humidity. This process is commonly referred to as compression set. The ability to predict recovery after the application of a compressive strain is crucial to both the manufacturers and end users of foam materials. Specific compression set test procedures have been established to quantify the extent of non-recoverable deformation in specific foam types but to date no general predictive approach exists. In this work, compression set (fixed strain) tests were undertaken on a cellular polyamide-6 material at various temperatures (-5°C to 90°C) and the foam recovery monitored over time periods in excess of those dictated by standard methods (ISO 1856 [1]). An empirical formula has been proposed to allow the prediction of recovery after compressive strain, covering recovery periods from 10 minutes to 24 hours (up to 168 hours at 23°C). © (2010) Trans Tech Publications, Switzerland.

Izzard V.G.,Kingston University | Hadavinia H.,Kingston University | Morris V.J.,Kingston University | Foot P.J.S.,Kingston University | And 2 more authors.
Polymers and Polymer Composites | Year: 2012

This paper presents experimentally determined compression sets and compression behaviour of two closed-cell, crosslinked foam materials; ZOTEK N B50 (Nylon 6) and ZOTEK N A30 (nylon/polyolefin alloy). This work forms the basis of future investigations into the post-impact behaviour of these foams. Compression set performance was measured at 25.0, 37.5 and 50.0% strain at nine temperatures ranging from -5 to 90 °C. Compression tests at constant strain rates were conducted at four temperatures between 23 to 90 °C. Finally compression tests at 23 °C were repeated at four strain rates between 0.3 and 550 hr -1 to determine strain rate dependency. The Nagy and Williams-Landel-Ferry scaling factor for strain rate and temperature were applied to the experimental results and equations were derived which allowed the performance of the two polyamide based foams to be interpolated over the strain rate and temperature range of study. The required material properties of interest of the base polymers have been assessed and are presented and discussed in relation to the performance of the foam materials. © Smithers Rapra Technology, 2012.

Breen A.F.,Sheffield Hallam University | Breen C.,Sheffield Hallam University | Clegg F.,Sheffield Hallam University | Doppers L.-M.,Zotefoams Plc | And 4 more authors.
Polymer (United Kingdom) | Year: 2012

The simultaneous ingress of acetone and water into dried PVOH-clay nanocomposites containing 2.5 wt% or 5 wt% of well dispersed Na-Cloisite, using FTIR-ATR, has been compared with that into pure PVOH films. The rate at which water and acetone moved through the PVOH films is significantly reduced (i) at high acetone concentrations and (ii) when clay is incorporated in the PVOH film. For example, it takes 9 min and 17 min for water and acetone, respectively, to saturate a 25 ± 5 μm PVOH film containing 2.5 wt% of well dispersed clay when the acetone:water ratio is 90:10 v/v compared with ca. 1 min for a pure PVOH film when the acetone:water ratio is 70:30 v/v. The presence of significant quantities of water in the PVOH (nanocomposite) films was necessary before acetone began to permeate the film. The acetone entering the evanescent field was always highly hydrated even if the water content of the reservoir in contact with the film was low. There was no substantial evidence that the presence of clay altered the way in which the PVOH interacted with the acetone:water mixtures. The clay only acted to increase the tortuosity of the path through the film to the ATR prism. © 2012 Elsevier Ltd. All rights reserved.

Izzard V.G.,Kingston University | Bradsell C.H.,Kingston University | Hadavinia H.,Kingston University | Morris V.J.,Kingston University | And 3 more authors.
Key Engineering Materials | Year: 2012

One of the primary applications of polymer based cellular solids is to act as an energy absorbing material during impact where compressive strain rates may reach 500-800/s. In reality, impacts occur over a wide range of temperatures and velocities at different angles of incidence. Understanding and modelling the behaviour of the polymer foams requires characterisation of the material response in detail. The stress-strain response that covers both compressive and tensile behaviour for a wide range of strain rates and temperatures are needed to characterize the mechanical performance of polymer foams as polymeric foams are highly nonlinear materials that undergo large deformation in crashworthiness related cases. It is reported in literature that any increase or decrease in temperature over the glass transition region can cause changes by order of magnitude in elastic modulus of polymeric foams. However, creation of cross linking at high temperature can affect the elastic modulus. In this work, the behaviour of two, polyamide-6 (PA-6) based closed cell foams at elevated temperatures were investigated covering the glass transition temperature. This work presents the variation of elastic and tangent modulus of two low densities PA-6 and PA-6/polyolefin (Nylon alloy) based foams. Empirical equations have been proposed to allow the prediction of modulus over a temperature range of 23°C to 120°C for these materials. © (2012) Trans Tech Publications.

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