title: Development of Reaction Injection Moulded Polyurethane Foam Including Assessment of Densification and Reinforcement for use as a Structural Core in Rotationally Moulded Products

authors: Maarhuis, Nicholas Gerard

subjects: foam

abstract: To improve the performance of specific rotomoulded products being developed at a local company, reinforcement of the hollow core of the products with reaction injection moulded polyurethane (RIM PU) foam was investigated. Improvement of the foam mechanical properties was also investigated, with density variation and the addition of short glass fibre reinforcement. 

Testing showed the foam's mechanical properties were not directly relative to density. When foam density was doubled from 300 to 600kg/m3, the tensile strength increased by a factor of 2.7 and the modulus by a factor of 2.5. For ME1020 (fibre type) 6mm chopped fibre reinforced foam, these increases were larger, at factors of 3.0 and 2.6 for strength and modulus, respectively. For 300kg/m3 foam, fibre made negligible difference to the tensile strength, but the ME1020 reinforced foam was found to have 29% higher modulus than the neat foam at the same density (for 5wt% fibre composites). The 101C (fibre type) reinforced foam performed poorly, even showing a decrease in strength when compared to the neat foam at 600kg/m3 (for 5wt% fibre composites). The bending creep properties of reinforced foam was found to be higher than that of the neat foam in most cases, with ME1020 fibre composite foam performing better than 101C fibre reinforced composites in all cases. 5wt% ME1020 fibre reinforced foam was found to have impact strengths over twice that of neat foams at the same density. Impact strength improvements were also seen for 101C fibre reinforced foam, but to a lesser extent for both foam densities tested.

Morphological analysis of foam tensile fracture surfaces was undertaken and many interesting observations were made. Features such as cell elongation and fibre alignment with the foam flow direction were consistent with foam literature, but some unique features were observed. These include a localised 'string' cell packing trend, and also microscopic areas of localised plastic deformation in cell walls, which were visible as wrinkled surfaces on the foam cell walls.  


Modification of the (rotomoulded) skin to foam interface was investigated, as this parameter will likely affect the service performance of the whole product. Experimentation with various methods to increase the skin/foam interfacial shear strength was undertaken, and large improvements were attained with methods trialled and developed. These included adding particles to the rotomoulding charge, which became embedded in the inner skin of the moulded part, and protrude from the inner surface. These particles 'key' into the foam which fills the product's hollow core. Other interfacial shear strength improvement concepts for equipment to be developed were also proposed. One concept proposed is an innovative modification to plasma treatment equipment currently available, which could be used to treat the inner surface of hollow products, to improve the bonding between the inner rotomoulded surface and the foam. Another concept is proposed which may oxidise the inner rotomoulded part surface, but, only at the very end of the rotomoulding cycle, so that the bulk polymer is not degraded. The purpose of this deliberate oxidation is to achieve results similar to those attained by plasma or flame treatment currently used by industry for improving the wettability of PE products.

text: Development of Reaction Injection Moulded Polyurethane Foam Including Assessment of Densification and Reinforcement for use as a Structural Core in Rotationally Moulded Products To improve the performance of specific rotomoulded products being developed at a local company, reinforcement of the hollow core of the products with reaction injection moulded polyurethane (RIM PU) foam was investigated. Improvement of the foam mechanical properties was also investigated, with density variation and the addition of short glass fibre reinforcement. 

Testing showed the foam's mechanical properties were not directly relative to density. When foam density was doubled from 300 to 600kg/m3, the tensile strength increased by a factor of 2.7 and the modulus by a factor of 2.5. For ME1020 (fibre type) 6mm chopped fibre reinforced foam, these increases were larger, at factors of 3.0 and 2.6 for strength and modulus, respectively. For 300kg/m3 foam, fibre made negligible difference to the tensile strength, but the ME1020 reinforced foam was found to have 29% higher modulus than the neat foam at the same density (for 5wt% fibre composites). The 101C (fibre type) reinforced foam performed poorly, even showing a decrease in strength when compared to the neat foam at 600kg/m3 (for 5wt% fibre composites). The bending creep properties of reinforced foam was found to be higher than that of the neat foam in most cases, with ME1020 fibre composite foam performing better than 101C fibre reinforced composites in all cases. 5wt% ME1020 fibre reinforced foam was found to have impact strengths over twice that of neat foams at the same density. Impact strength improvements were also seen for 101C fibre reinforced foam, but to a lesser extent for both foam densities tested.

Morphological analysis of foam tensile fracture surfaces was undertaken and many interesting observations were made. Features such as cell elongation and fibre alignment with the foam flow direction were consistent with foam literature, but some unique features were observed. These include a localised 'string' cell packing trend, and also microscopic areas of localised plastic deformation in cell walls, which were visible as wrinkled surfaces on the foam cell walls.  


Modification of the (rotomoulded) skin to foam interface was investigated, as this parameter will likely affect the service performance of the whole product. Experimentation with various methods to increase the skin/foam interfacial shear strength was undertaken, and large improvements were attained with methods trialled and developed. These included adding particles to the rotomoulding charge, which became embedded in the inner skin of the moulded part, and protrude from the inner surface. These particles 'key' into the foam which fills the product's hollow core. Other interfacial shear strength improvement concepts for equipment to be developed were also proposed. One concept proposed is an innovative modification to plasma treatment equipment currently available, which could be used to treat the inner surface of hollow products, to improve the bonding between the inner rotomoulded surface and the foam. Another concept is proposed which may oxidise the inner rotomoulded part surface, but, only at the very end of the rotomoulding cycle, so that the bulk polymer is not degraded. The purpose of this deliberate oxidation is to achieve results similar to those attained by plasma or flame treatment currently used by industry for improving the wettability of PE products.

year: 2008

title: The role of dispositional mindfulness in employee readiness for change during the COVID-19 pandemic

authors: Roemer, Anja

subjects: readiness for change

abstract: Purpose
The coronavirus disease 2019 (COVID-19) pandemic has forced organisations to change the way they work to maintain viability, even though change is not always successfully implemented. Multiple scholars have identified employees' readiness for change as an important factor of successful organisational change, but research focussed on psychological factors that facilitate change readiness is scarce. The purpose of the present study was to investigate whether employee dispositional mindfulness contributes to readiness for change.

Design/methodology/approach
Employees (n = 301) from various industries in New Zealand participated in an online survey shortly after the local COVID-19 lockdown ended. The employees' levels of mindfulness, readiness for change, well-being and distress were assessed using well-validated psychometric scales. Multiple regression analyses tested the effect of mindfulness on readiness for change, with well-being and distress as moderating variables.

Findings
The results show that the effect of mindfulness on readiness for change is moderated by both well-being and distress. Mindfulness has a positive, significant effect on readiness for change when levels of well-being are high and levels of distress are low.

Practical implications
These findings have important implications for organisations who aim to promote readiness for change in their employees. Even though mindfulness has been shown to be beneficial, organisations also have to consider the mental states of their employees when managing change.

Originality/value
This study provides empirical evidence that dispositional mindfulness may facilitate the employees' readiness for change, but only when levels of well-being are high and distress are low.

text: The role of dispositional mindfulness in employee readiness for change during the COVID-19 pandemic Purpose
The coronavirus disease 2019 (COVID-19) pandemic has forced organisations to change the way they work to maintain viability, even though change is not always successfully implemented. Multiple scholars have identified employees' readiness for change as an important factor of successful organisational change, but research focussed on psychological factors that facilitate change readiness is scarce. The purpose of the present study was to investigate whether employee dispositional mindfulness contributes to readiness for change.

Design/methodology/approach
Employees (n = 301) from various industries in New Zealand participated in an online survey shortly after the local COVID-19 lockdown ended. The employees' levels of mindfulness, readiness for change, well-being and distress were assessed using well-validated psychometric scales. Multiple regression analyses tested the effect of mindfulness on readiness for change, with well-being and distress as moderating variables.

Findings
The results show that the effect of mindfulness on readiness for change is moderated by both well-being and distress. Mindfulness has a positive, significant effect on readiness for change when levels of well-being are high and levels of distress are low.

Practical implications
These findings have important implications for organisations who aim to promote readiness for change in their employees. Even though mindfulness has been shown to be beneficial, organisations also have to consider the mental states of their employees when managing change.

Originality/value
This study provides empirical evidence that dispositional mindfulness may facilitate the employees' readiness for change, but only when levels of well-being are high and distress are low.

year: 2021

title: District plan implementation under the RMA: Confessions of a resource consent

authors: Day, Maxine

subjects: New Zealand

abstract: This report focuses on results from Phase 2 of PUCM - the quality of plan
implementation in six district councils selected for their range of plan quality and
capacity to plan. Only those results considered to be important for assisting the six
councils (and others) to improve implementation of their plans are included in this
report. The findings and recommendations, both specific and general, ought to be
instructive for other councils, thereby helping to improve their plans and
implementation processes. Since hapu/iwi interests formed a key component of the
research, the outcomes will help enhance their case for better consideration of their
interests when dealing with local government. As well, many of the findings and
recommendations relate to matters of governance and capacity building that require
Government action, which until done will make it difficult for councils to achieve
quality plans and implementation processes.

text: District plan implementation under the RMA: Confessions of a resource consent This report focuses on results from Phase 2 of PUCM - the quality of plan
implementation in six district councils selected for their range of plan quality and
capacity to plan. Only those results considered to be important for assisting the six
councils (and others) to improve implementation of their plans are included in this
report. The findings and recommendations, both specific and general, ought to be
instructive for other councils, thereby helping to improve their plans and
implementation processes. Since hapu/iwi interests formed a key component of the
research, the outcomes will help enhance their case for better consideration of their
interests when dealing with local government. As well, many of the findings and
recommendations relate to matters of governance and capacity building that require
Government action, which until done will make it difficult for councils to achieve
quality plans and implementation processes.

year: 2003-04-15