Characterization of graded polyurethane elastomer by FTIR

Abstract

Polyurethane elastomers with graded structure were prepared in the graded temperature field. The samples were characterized by FTIR technology. The results show that the degree of microphase separation in the samples decreases with the decrease of the curing temperature. As far as the molar ratio of NH 2 and NCO is concerned, the sample exhibits better graded morphology when the ratio is 0.95. The transparence of the samples prepared also changes gradually, increasing along the direction, in which temperature decreases.FGM, polyurethane, graded, transparence, microphase separation, FTIR Researchers have shown great interesting and efforts to develop the functionally graded material (FGM), since its concept was proposed by Japanese material scientists in the 1980s [1] . FGM is a new class of material that exhibits property changing gradually with spatial position. The property gradient in the material is caused by a position-dependent chemical composition, microstructure, or atomic order [2] . In the last twenty years, great progressing of research about FGM has been made. However, as a new field, research focuses and hotspots are still basic problems, such as manufacturing methods, characterization and performance evaluation, and optimization design [2][3][4][5] .Polyurethane elastomers are an important type of polymer material with excellent physical and chemical properties. And, many applications have been found in different fields. It is promising to find new performances and applications if introducing the FGM concept into the preparation of polyurethane elastomers. It is a pity that there are few studies about polyurethane elastomers with graded structure. Generally, polyurethane appears as a composition of the FGM prepared by forming IPNs or blends. Furukawa et al. [6] prepared graded polyurethane elastomer, whose aggregation structure changed gradually, by controlling and keeping the temperature gradient of the curing mould. Differential scanning calorimetry, polarized optical microscopy and dynamic mechanical analysis were used to characterize the graded structure.Microphase separation is a major characteristic of polyurethane elastomers. It is responsible for many properties of polyurethane. Thus, the gradual change of degree of microphase separation will lead to gradual change of property. In this study, the system TDI-PPG-MOCA was selected to prepare the graded polyurethane by curing in the graded temperature field. FTIR technique was used to characterize its graded structure.

The molecular arrangement of Bifenthrin® in ether based polyurethane: Designing a synthetic termite barrier

“…Curing the EPU/Bifenthrin® blends followed the same procedure as for the unblended EPU described earlier. Previous work8 has shown that in a sample containing nominally 4 wt % Bifenthrin®, ∼ 10% of the Bifenthrin® is lost during the degassing and curing procedure.…”

“…Bifenthrin® is comprised of aromatic and nonaromatic groups, Figure 1, and thus there exists the possibility of interaction between the aromatic groups of the active and the isocyanate group of the EPU, in this case toluene di‐isocyanate (TDI). Although FTIR has been used to analyze EPU8 and pyrethroids9 separately, their interactions have not been explored. The Bifenthrin® molecule also contains fluorine and this element presents an excellent marker for X‐ray photoelectron spectroscopy (XPS) analysis of the distribution of the active within the EPU and its presence on the surface.…”

Toolbox for optimizing anti‐erosion protective coatings of wind turbine blades: Overview of mechanisms and technical solutions

“…They demonstrated that “winning strategy in term of more absorbed energy with a low transmitted force could consist of placing the ‘hardest' layer as the first impacted layer and the ‘weakest' layer in contact with the protected structure to reduce the transmitted force.” This effect is strong only under high impact speed. Also, graded PUs might have potential for antierosion coatings . However, there are not enough studies about their application in coatings.…”

“…Also, graded PUs might have potential for antierosion coatings. 56 However, there are not enough studies about their application in coatings.…”

Preparation and Evaluation of Nanofibrous Hydroxypropyl Cellulose and β-Cyclodextrin Polyurethane Composite Mats

“…Among them, polyurethanes are an important and versatile class of polymers that have found widespread applications in biomedical field [10]. Generally, polyurethane based materials are widely used in coatings [11], paints [12], foams [13], elastomers [14][15][16], adhesives [17] and medical devices [18][19][20]. Thereby, polyurethane based materials have been the subject of several studies aimed to design advanced materials with high performances [21][22][23].…”