Abstract:Polyurethane foam is a kind of polymer composite material. The foaming turgidity and reaction temperature of polyurethane foam are closely related to its mechanical properties. According to our present knowledge, this study is the first time that fiber optic sensing technology has been applied to monitor the dynamics change in the foaming turgidity and reaction temperature of polyurethane foam during its preparation. The effects on the foaming expansion force, contractile force, and reaction temperature are st… Show more
“…The mechanical properties of polyurethane depend mainly on the cell structure, including cell size [ 33 , 34 , 35 ], cell content, anisotropy of the cell structure [ 36 , 37 , 38 ], closed (cell content), and wall thickness of the cell [ 39 ]. The formation stages of polyurethane foams include four phases cell nucleation, cell growth, microphase separation, and polymerization [ 40 ]. In the process of foaming to molding, ambient temperature, raw material ratio, mold temperature, material temperature, and curing time affect the foaming rate and the final cell structure morphology of polyurethane foams.…”
Section: Influence Of Temperature On Polyurethane Foam Properties Dur...mentioning
Temperature is one of the main factors affecting the properties of polyurethane foams, and there are large differences in the mechanical properties of polyurethane foams at different temperatures. To understand the effect of temperature on the mechanical properties of polyurethane foams and to provide a theoretical basis for the application of polyurethane foams in extreme environments, this paper systematically describes the research on the effect of mold temperature, raw material temperature, and environmental temperature on the microstructure and mechanical properties of polyurethane foams in the formation and service stages of rigid polyurethane foams by domestic and foreign scholars, and summarizes the effect of temperature on the mechanical properties of polyurethane foams and the mechanism of action. A review of the literature shows that the effect of different temperatures on the mechanical properties of polyurethane foams can be summarized. The literature review shows that there are certain changes in the foaming process, pore structure, and mechanical properties of polyurethane foams at different temperatures, and the increase in temperature generally leads to the increase in pore size, decrease in density, and decrease in mechanical properties of polyurethane foams.
“…The mechanical properties of polyurethane depend mainly on the cell structure, including cell size [ 33 , 34 , 35 ], cell content, anisotropy of the cell structure [ 36 , 37 , 38 ], closed (cell content), and wall thickness of the cell [ 39 ]. The formation stages of polyurethane foams include four phases cell nucleation, cell growth, microphase separation, and polymerization [ 40 ]. In the process of foaming to molding, ambient temperature, raw material ratio, mold temperature, material temperature, and curing time affect the foaming rate and the final cell structure morphology of polyurethane foams.…”
Section: Influence Of Temperature On Polyurethane Foam Properties Dur...mentioning
Temperature is one of the main factors affecting the properties of polyurethane foams, and there are large differences in the mechanical properties of polyurethane foams at different temperatures. To understand the effect of temperature on the mechanical properties of polyurethane foams and to provide a theoretical basis for the application of polyurethane foams in extreme environments, this paper systematically describes the research on the effect of mold temperature, raw material temperature, and environmental temperature on the microstructure and mechanical properties of polyurethane foams in the formation and service stages of rigid polyurethane foams by domestic and foreign scholars, and summarizes the effect of temperature on the mechanical properties of polyurethane foams and the mechanism of action. A review of the literature shows that the effect of different temperatures on the mechanical properties of polyurethane foams can be summarized. The literature review shows that there are certain changes in the foaming process, pore structure, and mechanical properties of polyurethane foams at different temperatures, and the increase in temperature generally leads to the increase in pore size, decrease in density, and decrease in mechanical properties of polyurethane foams.
“…Literature reports that gradual temperature reduction during PU reaction denotes the onset of curing stage. 62 In this case, the PU matrix in the nearby vicinity of the lower-temperature aluminium mould might have bypassed the cell growth stage into the induced curing stage, while foaming stages proceed normally as they become farther from the mould surface. Further study is underway to validate this finding.Figure 6.(a) Post-compression image of PU foam sample with 5 wt % Na-MMT; and (b) optical microscopy of ‘integral skin’ of PU foam sample with 5 wt % Na-MMT.…”
This paper presents the experimental works on rigid palm oil-based polyurethane (PU) foam reinforced with sodium-montmorillonite (Na-MMT). Filler loading was varied between 1 and 10 wt %., and the obtained foam was characterized for its combustibility, morphology, thermal stability, and mechanical response. Exfoliated clay microstructure was exhibited at lower Na-MMT loadings. Addition of nanoclay into the PU foam failed to impart any discernable improvement with regards to its flammability, believed due to stronger influence of low-functionality palm oil polyol used. Apparent improvement in thermal stability was observed at low clay amounts. Foam with finer cell size was obtained in the presence of Na-MMT, however only until a certain loading limit. Compressive strength generally increases with increasing clay content, but after 3 wt % the property deteriorated. Peculiarly, compressive strength rose again at 5 wt % and 6 wt % – postulated due to additional load-bearing effect of ‘integral skin’ – before plummeting back again beyond this value.
“…This directly affects the performance properties of the obtained polyurethane foams [48][49][50]. The structure of the polyurethane matrix depends not only on the designed formulation but also on the conditions of the foaming process [51]. A number of different processes take place during the preparation of flexible foams.…”
The management of by-products and waste from agriculture and the agri-food industry is a challenge for the plastics industry. Flexible polyurethane foams (EPPUR) containing ground corncake from corn oil production were obtained. The influence of the bio-filler on the physico-mechanical and thermal properties of synthesized flexible polyurethane foams was investigated. The content of corncake ranged from 0 php (part per 100 parts of polyol) to 10 php. Open-cell flexible polyurethane foams with a favorable comfort factor were obtained. The lower reactivity of the developed polyurethane systems was conducive to the formation of cells of slightly smaller sizes but of a more regular shape in comparison with the foam not modified with the bio-filler. Measurements of the mechanical properties indicated that the modified foams held had similar or even better properties than the reference sample without bio-filler.
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