Performance Of Polyurethane Research Articles

Effects of Cold Plasma Treatment on the Performance of Polyurethane Laminated Glass

The delamination of polyurethane (PU) laminated glass usually occurs at the interface between PU and inorganic glass. To prevent interlaminar delamination of PU and inorganic glass, PU was treated with cold plasma. The transparency of PU improved after cold plasma treatment. The cold plasma-treated PU showed 2 to 6 % higher transmittance than untreated PU. The adhesive strength of PU laminated glass increased by at least 96 % after cold plasma treatment. The adhesive strength of untreated PU samples rapidly decreased with increased hygrothermal aging time, whereas treated PU maintained almost 93 % of the original adhesive value even after hygrothermal aging for 30 days. FTIR analysis shows that –CO–O–C–, –C=O, and –CO–N groups appeared on the surface of cold plasma-treated PU, which resulted in the formation of hydrogen bonds at the interface between PU and silicate glass. After cold plasma treatment, the contact angle of PU changed from 105° to 79°, and the surface roughness of PU membranes changed from an average value of 19.74 to 57.16 nm.

Improvement of Thermal Polyurethane Adhesive Compositions Parameters by Modification with Zeolite

The aim of this study is to improve the heat resistance performance of polyurethane based adhesives for the manufacture of shoes. Four polyurethane adhesive compositions most used in the domestic shoe industry have been investigated: PU-503, VU-252, KYSPO-1 and D-274. The main components of polyurethane compositions are urethane rubber, zeolite, ethyl acetate and acetone. It has been found that modification of VU-252, KYSPO-1 and D-274 with zeolite in the amount of 0.5-1% allow to increase the heat resistance to 150° C while that of PU-503 - to 200° C. Besides it has been found that adhesive compositions can be recommended for the manufacture of special fire-resistant shoes that could withstand high thermal loads.

Functionalized graphene nanoplatelets for enhanced mechanical and thermal properties of polyurethane nanocomposites

In the evolution of high performance graphene-based polymer nanocomposites, homogeneous dispersion of graphene nanoplatelets in the polymer matrix and exact interface control are difficult to achieve due to the potent interlayer cohesive energy and surface inactiveness of the nanocomposites. Herein, we present an effective way to fabricate high performance polyurethane (PU) nanocomposites via the incorporation of functionalized graphene nanoplatelets (f-GNP) during in situ polymerization. The f-GNP/PU nanocomposites exhibited a significant improvement in terms of their mechanical, thermal, and shape recovery properties. The modulus of the f-GNP/PU nanocomposites at 2wt% graphene nanoplatelets loading is ten times greater than that of the pure PU sample. The breaking stress and shape recovery showed a highly improving trend with increasing wt% of f-GNP. An unprecedented enhancement of thermal stability at 30°C compared to the pure PU is also found at 2wt% loading of f-GNP via in situ polymerization.

Manufacturing and Sewing Performance of Polyurethane and Polyurethane/Silicone Coated Fabrics

In this research, polyurethane (PU) and polyurethane/silicone (PU/silicone) coated fabrics were manufactured and the effects of coating parameters such as coating material, coating technique, and production parameters on sewing performance of the coated fabrics were investigated. During manufacturing processes, one fabric sample having cotton as raw material and having plain weave was used as the base fabric. The base fabric was coated with two coating materials as PU and PU/silicone by two coating techniques such as rotary screen coating and blade coating with systematically changing production parameters (screen pressure and contact angle). Therefore, twelve coated fabric samples having different technical specifications were produced. Due to the limited number of studies in related literature, sewing performance of the coated fabrics was investigated by the tensile properties of the unsewn and the sewn fabrics and also the seam efficiency values were compared. Variance analyses were used to determine and evaluate the effects of coating parameters on seam performance of the coated fabrics.

Analysis of non-covalent interactions between the nanoparticulate fillers and the matrix polymer as applied to shape memory performance

Non-covalent interactions between filler particles and polyurethanes were investigated using fluorescence emission spectroscopy. The results were used in the analysis of shape memory (SM) performance of polyurethanes. Composites of shape memory polyurethane (SMPU) and carbon nanofiber (CNF), oxidized carbon nanofiber (ox-CNF), organoclay, silicon carbide, and carbon black were prepared from diphenylmethane diisocyanate, 1,4-butanediol, and poly(caprolactone)diol. It was revealed by fluorescence emission spectroscopy that primarily the urethane groups located in the hard segments of SMPU interacted with the polar functional groups on filler particles. A close correlation between the extent of non-covalent filler–matrix interactions, soft segment crystallinity, and SM properties of polyurethane composites was discussed. It was observed that weak non-covalent interactions of polymer chains with CNF and SiC particles caused significant reductions in soft segment crystallinity of SMPU and hence the shape memory properties of the composites.

Super Low Density Polyurethane Systems for Sports Shoes

This paper describes in detail a new concept of producing super light weight (0.24-0.26 g/cm3) polyurethane (PU) midsoles to compete with EVA for sports shoes. Materials for the midsole of the dual density sport shoes are composed of PU or EVA. Though PU midsole has good cushioning (resilience), adhesive and processing properties compared with conventional EVA systems, it is difficult to reduce the molding foam density drastically. Recently, developments for high performance PU systems have focused on reducing the density while maintaining high physical properties. To solve this problem, we have developed several new progressive technologies. The first uses a polyesterpolyol with functional cohesive units in the main polymer chains. Using this polyesterpolyol, the hard segments of PU become tougher. The second is distributing the cell diameter gradient toward the center of the foam cross section. The split tear, which is one of the most important physical properties for a midsole, has been improved drastically. These new technologies are the best way to spread super light weight PU to new applications and markets.

Oxazolidine curing agents

This review addresses trends in the development of high performance polyurethane (PU) and its subclass coatings. Changes in the understanding the technical requirements and properties, along with novel approaches in creating high performance PU films are discussed. Some discussion of developments leading to the current status is provided, along with opportunities for the development of architectural, domestic and automotive coatings from carbamate chemistry. The review also focuses on the chemistry of PU, the importance of side products such as biuret, allophanate formation, as well as different low VOC PU coatings such as moisture-cured PU-urea, polyurea, PU-imide, UV cure and waterborne PU coatings. A brief description of functionalized dendritic/hyperbranched polymers, different monomers and synthetic approaches, and their use in the PU coating sector is addressed. In the context of nanostructuring, sol–gel chemistry to formulate ceramer coatings and use of functionalized nanomaterials in PU coatings is described. This portion also includes silica grafting and functionalization of nanosilica particles, polyhedral oligomeric silsesquioxane and the use of bridged polysilsesquioxanes in PU coatings. A wide variety of fillers, whiskers and fibers as well as clay and wollastonites with structural modification is described for use in nanocomposite PU coatings, with special emphasis on the latest development in PU-layered silicate nanocomposites.The use of different reactive-type organophosphorus compounds, aziridinyl curing agents in aqueous PU dispersions, phosphazenes, organo-boranes such as different carboranes for use in the formulation of flame retardant coatings is described. Since surface properties determine the resistivity of coatings towards corrosive chemicals, moisture and dirt repellency, a portion of the review will also be devoted towards modification of surface properties using fluoropolymer, and the synthesis and a brief description of the available fluorinated diols is given.

Underwater performance of polyurethane - PETN explosives

Abstract Detonation velocities and pressures for Polyurethane Foam - PETN charges at a density of 0.6 g/cm3 have been determined experimentally and compared to theoretical predictions obtained by the TIGER code, using the BKW equation of state with the RDX fit and a new fit developed for low density explosives. It was found that the explosive exhibits a non-ideal performance at small charge diameters. In order to determine the equation of state of the detonation products of the explosive in underwater applications, aquarium experiments were conducted and compared with hydrodynamic calculations performed by the TDL code. HOM equation of state parameters were obtained by using a trial and error approach so that good agreement is observed between experimental detonation velocities and gas expansion histories underwater. Using this technique, HOM parameters were obtained in three different charge diameters. It was found that at a diameter of 70 mm the detonation behaviour of the explosive is ideal while non-i...