The new issue 3/2020 of PU Magazine International has been published!
In this issue we present technical articles on methylal blowing agents by Sendijarevic et al. (Troy Polymers, Inc, Lambiotte, Holland Applied Technologies), development and optimization of rigid foams by Obi et al. (PolyFoam Consulting, Huntsman Corporation), and silicone surfactants by Nadal and Lopez (Concentrol).
You can also read about topics such as the impact of the Corona pandemic on the automotive markets and best strategies for recycling of wind turbine blades.
This issue contains as well the first part of a two-part series on the use and recycling of plastics by Bernhard W. Naber.
Featured technical articles are:
- Decoupling the glass transition temperature and compressive strength in the development and optimization of rigid polyurethane foams
(B. Obi, PolyFoam Consulting LLC, L. Wu, S. Singh, Huntsman Corporation)
Cellular polymer foams are being increasingly used in applications which demand both good insulating and mechanical properties. The compressive modulus (E) and strength (Cs) along with the glass transition temperature (Tg) are important properties in the development of rigid polyurethane (PU) foams used in various applications, particularly in insulation applications. In this work, we outline a methodology based on established concepts in polymer science to predict the uniaxial compression modulus, strength and the glass transition temperature for rigid polyurethane foams as a function of the formulation design variables. Results of the analysis are validated with experimental results. This could greatly accelerate the development of new rigid polyurethane foam formulations. This type of methodology could also be used for formulation optimizations for product performance and cost.
- Performance of methylal blowing agent in rigid polyurethane foams and comparison to HFOs
(I. Sendijarevic, Troy Polymers, Inc., M. Beaujean, B. Labelle, Lambiotte, J. Rhodes, Holland Applied Technologies)
The polyurethane industry has already made major strides to meet the regulatory requirements to transition to low global warming potential (GWP) physical blowing agents. For use in rigid foams, common SNAP approved low GWP blowing agents commonly used in North America include pentanes and HFOs (1233zd(E) and HFO 1336mzz(Z)). Another viable option now available in North American market is methylal. Methylal has already been SNAP approved for most polyurethane applications. Compared to most other blowing agents, methylal offers superior solubility in most polyols and is generally highly compatible and stable with catalysts, surfactants, and flame retardants found in polyurethane systems. It also offers high blowing capacity, which is effectively twice that of available HFOs. Previous studies have demonstrated the benefits of using methylal in place or in combination with n-pentane and cyclopentane. In this paper, we are evaluating the performance of methylal in a model rigid polyurethane foam system as a drop-in replacement for a commercially available 1233zd(E) HFO. The impact of methylal on reactivity and functional performance parameter is evaluated, including blowing capacity, dimensional stability, compressive strength, and thermal conductivity. The results of this study can guide implementation of methylal in rigid polyurethane foam formulations.
- Silicone surfactants for low content of aldehyde and aromatic emissions in PU foam
(J. Nadal, A. Lopez, Concentrol)
Flexible PU foams were developed and used in car seats in the early 1950s. In the 1990s, the first low-emission foams were developed and, due to emanations control, were extended to subsurface materials used, such as seat cushions. Raw material suppliers were asked to explore the sources of the emanations and work with OEMs to reduce their overall quantity. At that time, silicone surfactants played a key role in low emissions. A general overview on the emissions and the analytical methods used to analyze PU foam emissions was published in 2018 , but it focused mainly on emissions under well-established methods such as VDA 278 , which is one of the standard European methods. As other markets such as the Asia-Pacific economic zone may have different requirements and quality standards when emissions are considered, we summarize in this paper the main volatile components currently monitored in this region and how they are analyzed. We also discuss analytical data regarding the contribution of silicone surfactants to emissions and how they can be improved to meet customer requirements.
- The old Plast and the Sea – part 1. Questions and comments on the use and recycling of plastics
(Bernhard W. Naber)
Nowadays the use of plastics is mainly perceived as a problem. And indeed, their extensive use is a double-edged sword. On the one hand, we cannot and do not want to do without plastics, because the diversity of polymers and their broad spectrum of properties enable applications where traditional materials fail. In addition to their undeniable benefits in everyday life, they are also the cause and the content of a wide range of environmental problems. This article looks at what speaks for and what against the extensive use of plastics. Part 1 deals with the advantages of plastics for our high-tech civilization and highlights the general possibilities, limits and economic and ecological costs of recycling. In part 2, different groups of plastics will be considered individually and examined for their recyclability. Raw material recycling and incineration are also addressed as possible end-of-life solutions.
Further information about the new issue at https://www.gupta-verlag.com/magazines/pu-magazine-international/03-2020.