Thermosetting polyurethane foams by physical blowing agents: Chasing the synthesis reaction with the pressure

Brondi, Cosimo; Caprio, Maria Rosaria Di; Scherillo, Giuseppe; Maio, Ernesto Di; Mosciatti, Thomas; Cavalca, Sara; Parenti, Vanni; Corti, M.; Iannace, Salvatore

doi:10.1016/j.supflu.2019.104630

Cited by 20 publications

(5 citation statements)

References 11 publications

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“…Table 4 shows the main processability parameters (density-

, thermal conductivity- k , thermal diffusivity- a , specific heat capacity- c s , typical layer thickness per AM technique- t layer,min obtained from different databases [ 48 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ], including the calculation of penetration depth ( d ).…”

Section: Methodsmentioning

confidence: 99%

Reliability-Based Evaluation of the Suitability of Polymers for Additive Manufacturing Intended for Extreme Operating Conditions

Rodríguez-Prieto

Primera

Callejas³

et al. 2020

Polymers

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A reliability engineering program must be implemented from the conceptual phase of the physical asset to define the performance requirements of the components and equipment. Thus, in this work, the aim is to find the most optimal solution to manufacture polymer-based parts for the nuclear power industry using additive manufacturing routes. This case study application has been selected because polymers processed by additive manufacturing (AM) can be well suited for nuclear applications. The methodology includes—firstly—an analysis of the suitability of materials based on high-temperature resistance, thermal aging and irradiation tolerance, considering operation conditions. Secondly, an analysis of materials’ processability considering their associated AM routes is performed based on thermal analysis and evaluation of physical properties of materials. A final assessment integrating the in-service suitability and AM processability is performed using a reliability approach, solving different emerging objective conflicts through defined constraints and selection criteria. According to the integrated in-service performance evaluation: Polypropylene-ethylene polyallomer (PPP), Epoxy (EP), Phenolics (Ph), Polyurethane (PU) and Acrylonitrile butadiene rubber (NBR) are the best options for mild operation conditions and EP, Ph and PU, considering high temperature along with radiation exposure. Considering AM techniques: EP and Ph can be manufactured using VAT photopolymerization-stereolithography (VP-SLA) with a good expected processability being these materials valid for high temperature environments. Consequently, this research work analyzes the viability, processability and in-service behavior of parts.

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“…Table 4 shows the main processability parameters (density-

Section: Methodsmentioning

confidence: 99%

Reliability-Based Evaluation of the Suitability of Polymers for Additive Manufacturing Intended for Extreme Operating Conditions

Rodríguez-Prieto

Primera

Callejas³

et al. 2020

Polymers

View full text Add to dashboard Cite

show abstract

“…A critical point is the synchronization of the decomposition and/or vaporization of the blowing agent with the initiation of the viscosification of the polymer material. [56,71,[79][80][81][82][83][84][85][86][87][88][89][90] It is indeed essential that the bubbles nucleate and grow in a certain viscosity window sometimes called the viscosity foaming window. [71,80] If the gas is released before the viscosity enter the foaming window, it will quickly diffuse through the polymer.…”

Section: B Chronology Of a Foaming Process -The Foaming Windowmentioning

confidence: 99%

Self-foaming polymers: Opportunities for the next generation of personal protective equipment

Monie

Vidil

Grignard

et al. 2021

Materials Science and Engineering: R: Reports

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“…These bubbles push through the pores formed by the CO 2 byproduct of the water/isocyanate reaction, providing interconnects between pores without affecting the synthesis reaction 26 . Chloroflurocarbons and hydrofluorocarbons (HFCs) have been previously used as physical blowing agents in PU foams, but both are known to destroy the ozone layer 34,35 . For example, Enovate (HFC‐254fa) is a physical blowing agent commonly used in PU SMP foam synthesis 36 .…”

Section: Introductionmentioning

confidence: 99%

“…26 Chloroflurocarbons and hydrofluorocarbons (HFCs) have been previously used as physical blowing agents in PU foams, but both are known to destroy the ozone layer. 34,35 For example, Enovate (HFC-254fa) is a physical blowing agent commonly used in PU SMP foam synthesis. 36 However, its commercial use is risky, because it is only available from a single supplier; additionally, the Environmental Protection Agency (EPA) considers its use unacceptable due to its potential to contribute to global warming.…”

mentioning

confidence: 99%

Shape memory polymer foams with tunable interconnectivity using off‐the‐shelf foaming components

Petryk

Haas

Vakil

et al. 2022

J Biomedical Materials Res

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The ability to easily and safety tune pore structures of gas-blown polyurethane shape memory polymer (SMP) foams could improve their outcomes as hemostatic dressings or tissue engineering scaffolds and enable overall commercialization efforts. Incorporating physical blowing agents into the polymer mix can be used to tune pore size and interconnectivity without altering foam chemistry. Enovate (HFC-254fa) is a commonly used physical blowing agent in gas-blown foams, but the Environmental Protection Agency (EPA) considers its use unacceptable because it is a hydrofluorocarbon that contributes to global warming. Here, off-the-shelf solvents accepted for use by the EPA, acetone, dimethyoxymethane (methylal), and methyl formate, were used as physical blowing agents by adding small volumes during foam fabrication.Increasing the physical blowing agent volume resulted in greater pore interconnectivity while maintaining SMP foam chemical and thermal properties. Pore size and interconnectivity also impacted cell and blood interactions with the foams. This work provides a safe and easy method for tuning SMP foam interconnectivity to aid in future commercialization efforts in a range of potential biomedical applications.

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Thermosetting polyurethane foams by physical blowing agents: Chasing the synthesis reaction with the pressure

Cited by 20 publications

References 11 publications

Reliability-Based Evaluation of the Suitability of Polymers for Additive Manufacturing Intended for Extreme Operating Conditions

Reliability-Based Evaluation of the Suitability of Polymers for Additive Manufacturing Intended for Extreme Operating Conditions

Self-foaming polymers: Opportunities for the next generation of personal protective equipment

Shape memory polymer foams with tunable interconnectivity using off‐the‐shelf foaming components

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