Types Of Polyurethanes Research Articles

Recent developments of Madhuca indica (Mahua) oil-based polymers: A mini review

Nowadays, the use of non-edible vegetable oils as the raw material for polymer development is growing in interest because of the scarcity and high demand for crude oil and also because of its eco-friendly approach. The utilization of non-edible oil to synthesize the applicable polymers reduces the usage of petrochemicals. To eliminate the reliance on petrochemicals, it is important to search for and extract alternate and domestic non-edible oils suitable for the synthesis of polymeric materials. This is now a promising research approach. The outstanding feature of indigenous, non-edible Madhuca indica oil (MO) is its chemical structure, with unsaturated sites and esters that are considerable ingredient polyols for the development of polymers. This review discusses the origin, structure and extraction of MO and systematically focuses on the recently developed polymers using oil as a renewable source of polyols. We have briefly reviewed MO-based polymeric materials such as alkyd resins like pentaalkyds for scratch resistance, glycerol alkyds for fly-ash coating, pentalkyd LC resins for display coating applications and epoxies of MO for biological coating materials. Also, the important polyurethanes in the pathways of MO-based fatty amide are transformed into the polyetherimide polyols through a step-growth reaction with bisphenol-A or bisphenol derivatives, which again react with isocyanates to produce MO-based PU for excellent adhesion and coating applications. Another type of waterborne polyurethane is made from polyesteramides. These PU coatings are used in the paint and pigment industries. We reviewed their synthesis and widespread use in coatings and composites.

Mechanical Properties of Green and Petroleum based Polyurethane as Grouting Materials

In this study, polyurethane grouting materials (PUG) were prepared using two different types of polyol which were castor-based polyol (CPUG) and petrochemical-based polyol (PPUG). Four different ratios of polyol (OH) to isocyanate (NCO) were used in this study. The effect of different compositions of Isocyanate on mechanical properties were investigated and compared. The flexural strength, and compression strength shows the increment with the increase of the NCO composition. Optimum flexural strength, flexural modulus, and compression strength obtained at composition of PPUG4 and CPUG4 with the ratio of NCO: OH, 2.6: 1. PPUG gives a higher value of mechanical strength as compared to CPUG, however, results obtained for both types of polyurethane are in the range of industrial PU grouting properties grade. The decrease in cell wall of CPUG and PPUG with the increase of NCO:OH indicating the increment in cell wall interaction resulting higher mechanical properties of PUG.

Current advances in polyurethane biodegradation

AbstractWhile plastics bring convenience to industrial production and daily life, serious environmental problems are always accompanied. Polyurethane is an important polymeric material with versatile applications, but it also accounts for severe plastic contamination worldwide. Since it is difficult for polyurethanes to be completely degraded under natural conditions, the discovery of polyurethane‐degrading microorganisms and correlative ‘polyurethanase’ enzymes brings hope to polyurethane biodegradation. Polyurethane materials can be divided into two major types: polyester‐polyurethane and polyether‐polyurethane. In this review, we summarize the biodegradation mechanisms of these two types of polyurethane and recent research progress on the biodegradation of polyurethane via both microorganisms and enzymes. Furthermore, solutions that could be taken into consideration for the biodegradation of polyurethane in the future are also discussed. © 2021 Society of Industrial Chemistry.

Experimental Research on Polymer-Based Coaxial Sealing Systems of Hydraulic Cylinders for Small Displacement Velocities.

Reducing friction in the coaxial sealing systems of hydraulic cylinders is one of the solutions for increasing the energy efficiency of industrial actuations. This is a requirement, particularly in the case of small velocities that carry the risk of eigen-vibrations and/or stick-slip. The authors discuss the experimental research conducted on three coaxial sealing systems made from thermoplastic polymer and polyurethane type materials. The paper presents the equipment and method used for the experimental determination of static and kinematic friction coefficients and discusses the subsequent results obtained to test different working parameters. The experimentally determined friction coefficients yielded a range of materials recommended for coaxial seals such as to minimize the occurrence of jerky operation.

Flow rates of double-lumen over-the-wire catheters for high-volume fluid resuscitation in large animal species.

To evaluate the maximum in vitro flow rate of 6 types of polyurethane over-the-wire double lumen catheters using both ports, for high volume fluid resuscitation in large animal species. University teaching hospital. Prospective in vitro experimental study. The flow rate of both ports of 6 polyurethane double lumen over-the-wire catheters (11 and 13-Fr, 15 and 20cm long, elliptical and tapered tip designs) and 2 types of infusion (with or without pressure bags) were tested on a factorial scheme (6×2) in triplicate, using commercial isotonic crystalloid (0.9% NaCl) and synthetic colloid (6% Hydroxyethyl starch, 130/0.4). Flow rates were influenced by catheter diameter, length, tip design and presence or absence of pressure bags (P<0.05). Mean flow rates during non-pressurized 0.9% NaCl infusion ranged from 584mL/min (35 L/h; 11-Fr x 15cm x tapered tip catheter) to 905mL/min (54 L/h; 13-Fr x 15cm x elliptical tip catheter). Mean flow rates during non-pressurized synthetic colloid infusion varied from 404mL/min (24 L/h; 11-Fr x 15cm x tapered tip catheter) to 724mL/min (43 L/h; 13-Fr x 15cm x elliptical tip catheter). Mean flow rates during pressurized infusion were 1.72 and 2.02 times greater than those obtained by gravity alone for 0.9% NaCl and synthetic colloid, respectively (P<0.05). Highest in vitro flow rates were achieved when larger diameter, shorter and elliptical tip catheters were used during 0.9% NaCl infusion. Catheter diameter, tip design but not length influenced the flow rate during synthetic colloid infusion. The use of pressure bags significantly increased the flow rate of all catheters, for both solutions.

Thiol-Ene Click-Inspired Late-Stage Modification of Long-Chain Polyurethane Dendrimers

The construction of well-defined polyurethane dendrimers is challenging due to the high reactivity of externally added or in situ formed isocyanates leading to the formation of side products. With a primary focus of dendrimer research being the interaction of the periphery and the core, we report the synthesis of a common polyurethane dendron, which allows for the late-stage variation of both the periphery and the core. The periphery can be varied simply by installing a clickable unit in the dendron and then attaching to the core and vice-versa. Thus, a common dendron allows for varying periphery and core in the final two steps. To accomplish this, a protecting group-free, one-pot multicomponent Curtius reaction was utilized to afford a robust and versatile AB2 type polyurethane dendron employing commercially available simple molecules: 5-hydroxyisophthalic acid, 11-bromoundecanol, and 4-penten-1-ol. Subsequent late-stage modifications of either dendrons or dendrimers via a thiol-ene click reaction gave surface-functionalized alternating aromatic-aliphatic polyurethane homodendrimers to generation-three (G3). The dendrons and the dendrimers were characterized by NMR, mass spectrometry, and FT-IR analysis. A bifunctional AB2 type dendritic monomer demonstrated this approach’s versatility that can either undergo a thiol-ene click or attachment to the core. This approach enables the incorporation of functionalities at the periphery and the core that may not withstand the dendrimer growth for the synthesis of polyurethane dendrimers and other dendritic macromolecules.

Totally Implantable Venous Access Device (Chemoport) in Oncology: Study of 168 Polyurethane Chemoport Catheter System.

Background Chemoport (totally implantable venous access device) and its catheter system are used to administer long-term chemotherapy in cancer patients. The objective of this study was to analyze the complications associated with chemoport insertion in various cancer patients. Material and Methods A total number of 168 chemoports along with polyurethane catheters were inserted in various cancer patients over a period of 3 years. 9.6 F polyurethane catheters were put by a team of surgical oncologists in operation theater under general or local anesthesia. Analysis of the complications was done until the chemoport was removed due to any reason. Results Out of 168 patients, 30 (17.85%) developed complications. Complications included arterial puncture, malposition of the catheter tip, pneumothorax, hematoma, seroma, deep vein thrombosis, fracture of the catheter, a reversal of port, infections, and thrombosis of the catheter. Only a few required premature port and catheter removal. Conclusion There was a low rate of complications associated with chemoport using a polyurethane type of catheter system. However, infection-related complications were comparatively more common in our series. Chemoport requires expert handling, patient education, strict follow-up, and dedicated teamwork to minimize complications.

Biodegradation of Different Types of Plastics by Tenebrio molitor Insect.

Looking for new, sustainable ways to utilize plastics is still a very pertinent topic considering the amount of plastics produced in the world. One of the newest and intriguing possibility is the use of insects in biodegradation of plastics, which can be named entomoremediation. The aim of this work was to demonstrate the ability of the insect Tenebrio molitor to biodegrade different, real plastic waste. The types of plastic waste used were: remains of thermal building insulation polystyrene foam (PS), two types of polyurethane (kitchen sponge as PU1 and commercial thermal insulation foam as PU2), and polyethylene foam (PE), which has been used as packaging material. After 58 days, the efficiency of mass reduction for all of the investigated plastics was 46.5%, 41.0%, 53.2%, and 69.7% for PS, PU1, PU2, and PE, respectively (with a dose of 0.0052 g of each plastic per 1 mealworm larvae). Both larvae and imago were active plastic eaters. However, in order to shorten the duration of the experiment and increase the specific consumption rate, the two forms of the insect should not be combined together in one container.

Study of the Aging of Cold-Cured SKU-PFL Type Polyurethane Filled with Waste Products

The article describes the results of aging of samples of cold-cured molded polyurethanes of SKU-PFL brand filled with zeolite and silica gel - wastes of petrochemical production. The samples were aged under normal climatic conditions for 5 years. Filling of the samples varied from 10 to 50 %wt. Investigations of physical and mechanical properties of the samples before and after aging were carried out, the basic indicators of material quality were calculated using Microsoft Office Excel package. As a result of researches it was established that after aging the basic physical and mechanical properties of cast polyurethanes of SKU-PFL brand of cold curing filled with zeolite and silica gel change insignificantly, however the best resistance to aging are in samples with 20 %wt. zeolite and 10 %wt. silica gel filling both before and after aging that allowed to recommend them for long-term use of articles.

The Influence of the Ceramic Nanoparticles on the Thermoplastic Polymers Matrix: Their Structural, Optical, and Conductive Properties.

This paper prepared composites under the free membranes form that are based on thermoplastic polymers of the type of polyurethane (TPU) and polyolefin (TPO), which are blended in the weight ratio of 2:1, and ceramic nanoparticles (CNs) such as BaSrTiO3 and SrTiO3. The structural, optical, and conductive properties of these new composite materials are reported. The X-ray diffraction studies highlight a cubic crystalline structure of these CNs. The main variations in the vibrational properties of the TPU:TPO blend induced by CNs consist of the following: (i) the increase in the intensity of the Raman line of 1616 cm−1; (ii) the down-shift of the IR band from 800 to 791 cm−1; (iii) the change of the ratio between the absorbance of IR bands localized in the spectral range 950–1200 cm−1; and (iv) the decrease in the absorbance of the IR band from 1221 cm−1. All these variations were correlated with a preferential adsorption of thermoplastic polymers on the CNs surface. A photoluminescence (PL) quenching process of thermoplastic polymers is demonstrated to occur in the presence of CNs. The anisotropic PL measurements have highlighted a change in the angle of the binding of the TPU:TPO blend, which varies from 23.7° to ≈49.3° and ≈53.4°, when the concentration of BaSrTiO3 and SrTiO3 CNs, respectively, is changed from 0 to 25 wt. %. Using dielectric spectroscopy, two mechanisms are invoked to take place in the case of the composites based on TPU:TPO blends and CNs, i.e., one regarding the type of the electrical conduction and another specifying the dielectric–dipolar relaxation processes.

Breakthrough in polyurethane bio-recycling: An efficient laccase-mediated system for the degradation of different types of polyurethanes.

Development of green, efficient and profitable recycling processes for plastic material will contribute to reduce the expanding plastic pollution and microplastics accumulation in the environment. Polyurethanes (PU) are versatile polymers with a large range of chemical compositions and structures. This variability increases the complexity of PU waste management. Biological recycling researchers have recently demonstrated great interest in polyethylene terephthalate. The adaptation of this route towards producing polyurethanes requires the discovery of enzymes that are able to depolymerize a large variety of PU. A laccase mediated system (LMS) was tested on four representative PU models, with different structures (foams and thermoplastics), and chemical compositions (polyester- and polyether-based PU). Size exclusion chromatography was performed on the thermoplastics and this revealed a significant reduction in the molar masses after 18days of incubation at 37°C. Degradation of foams under the same conditions was demonstrated by microscopy and compression assay for both polyester- and polyether-based PU. This study represents a major breakthrough in PU degradation, as it is the first time that enzymatic degradation has been clearly demonstrated on a polyether-based PU foam. This work is a step forward in the development of a sustainable recycling pathway, adapted to a large variety of PU materials.

The preparation and characteristics of high puncture resistant composites inspired by natural silk cocoon

Bombyx mori cocoon, a natural nonwoven material has excellent puncture resistance and unique structure. Based on the structure of cocoon, this paper designed a biomimicry composite, aiming to improve the static puncture resistance through polyurethane impregnated treatment. In this article, four different types of polyurethane (TPU 85 A, TPU 90 A, PEUR 855 A, PEUR 991 A) are selected and five concentration gradients (5, 7, 9, 11, 13 wt%) are set. The tensile and static puncture resistance of the impregnated composites and damaged morphology after puncture are systematically studied. The results show that the static puncture resistance of nonwovens impregnated by polyurethane is improved obviously. This study provides a new way to design better static puncture resistant materials.

Characteristics of Polycarbonate Soft Segment-Based Thermoplastic Polyurethane

The pre-experiment of the present study revealed that polyurethane (PU) synthesized using poly (hexamethylene carbonate) glycol (PHC) has high melt viscosity and is difficult to process. Therefore, poly (trimethylene carbonate) glycol (PTC) was employed to synthesize a PU product with low melt viscosity. First, four types of thermoplastic polyurethane (TPU) were formed through one-step solvent-free synthesis. TPU is presented in the format “TPU-X-Y,” with X representing the polyol (PTC or PHC, around 1000 molecular weight) and Y the chain extender (1,3-propane diol [PDO] or 1,4-butane diol [BDO]) used. The TPU was synthesized using a fixed molar ratio of (isocyanate):(polyol):(chain extender) = 2:1:1 and compared. The results indicated that chain entanglement often occurred among the long carbon chains of PHC. The synthesized TPU employed a property of PTC, namely converting polarity into reverse polarity in high temperatures, to resolve the high melt viscosity of TPU of the PHC series, which causes processing difficulties. The synthesized TPU-PTC-PDO exhibited favorable molecular arrangements. Given its polarity, TPU-PTC-PDO has outstanding tensile properties (strength at break: 41.10 ± 10.78 MPa; 100% modulus = 6.73 ± 0.12 MPa), making processing at lower temperatures (180 or 190 °C) feasible. With the inclusion of PTC, the synthesized polycarbonate TPU exhibits the advantages of polycarbonate and is suitable for a wide range of applications.

Wear of polyethylene and polyurethane elastomers used for components working in natural abrasive environments

This paper presents the results of research on an evaluation of the intensity of tribological wear of polymers used for machinery components. The research material consisted of four types of polyurethane and PE 1000 PE-UHMW polyethylene. The research on the intensity of abrasive wear employed two methods: ball-cratering and the spinning bowl method. The ball-cratering test was performed using an abrasive suspension made of distilled water and silicon carbide (SiC). For the “spinning bowl” method, clay was the abrasive material. Based on material mass and density loss measurements, volumetric wear of the samples, and the specific wear rate Kc was determined. According to the test results, polyethylene PE 1000 was characterized by the highest resistance to wear. In the spinning bowl test, a similar wear value was obtained for polyurethane elastomer of the highest hardness among the tested polyurethanes.

Carbon dioxide adducts from DOPO‐grafted polyethylenimines as both blowing agents and flame retardants for polyurethanes

AbstractThe high risk of flammability of polyurethane foams (PUFs) and the high global warming potentials of polyurethane (PU) blowing agents rank key problems to be solved in PUF industry. Herein, 9,10‐dihydro‐9‐oxa‐10‐phosphenanthrene‐10‐oxide (DOPO)‐grafted polyethylenimines (PEIs) are synthesized via Atherton–Todd reaction, with grafting rate ranging from 13.3% to 28.3%. The grafted PEIs further react with CO2 to obtain corresponding CO2 adducts (DOPO‐PEI‐CO2s). On the one hand, these CO2 adducts can disperse into PU foaming mixture to release CO2 as a climate‐friendly blowing agent. The resultant PUFs possess a density about 56 kg m−3 and a compressive strength over 200 kPa, suitable for some industrial applications. On the other hand, the DOPO grafting endows the PUFs with moderate flame retardancy, increasing the PUFs' limiting oxygen index value from 19.7 to 25 vol%, and decreasing the horizontal burning speed from about 360 mm min−1 down to 130 mm min−1. This study for the first time provides a type of polyurethane (PU) raw material that can serve as both blowing agents and flame retardants.

Enhanced outdoor durability of polyurethane nanocomposite coatings with green reduced graphene oxide nanoplatelets

Obtaining the highest possible level of weathering resistance to protect the polymeric composites against sunlight and free radicals is the primary function of every exterior composite, such as polyurethane (PU). In this paper, a typical PU matrix was modified by two differently reduced graphene oxide nanosheets to enhance long-term weathering stability. The synthesized graphene oxide nanosheets were reduced by Nettle leaves extract as a green reductant and hydrazine as a typical reducing agent. The graphene oxide and two reduced species were embedded in PU to investigate their impact on weathering stability. Several techniques were employed to assess the weathering performance during 1400 h exposure to artificially accelerated conditions. Achieving superior weathering performance approved the effective role of reduced graphene oxide (especially green reduced) in elevating weathering stability of PU nanocomposites. The active mechanisms involved in such improvement were extensively discussed.

Effect of Nanoparticles on Acoustics Properties of Polyurethane Foam

Abstract:Noise pollution is growing in the modern century, with population growth and the advancement of manufacturing, which is the cause of many social and urban anomalies. Also, noise pollution leads to exhaustion and decreased efficiency in the workplace. We first define the sound and its properties in this article, then we discuss polyurethane as one of the most significant members of the polymer family and we examine polyurethane foams among the different types of polyurethane. Sound is a mechanical wave that requires transmitting through an environment. Polymers minimize and remove wave energy by viscous loss due to their viscoelastic properties, especially their viscous regions, and absorb sound. The literature review showed that adding nanoparticles improves the properties of polyurethane foam, especially the acoustic properties of polyurethane foams. By increasing the sound propagation paths through the polymer sample, these nanoparticles increase the likelihood of sound wave attenuation through viscous loss. These nanoparticles are classified into various forms according to the aspect ratio, like plate-like nanoparticles such as graphene and graphene oxide, nanotubes containing carbon nanotubes, and particulate nanoparticles containing metal oxides such as zinc oxide, and nano clays that have been examined by many researchers in polyurethane foam samples to study the effect of each nanoparticle on sound absorption.

Optical, Structural, and Dielectric Properties of Composites Based on Thermoplastic Polymers of the Polyolefin and Polyurethane Type and BaTiO3 Nanoparticles.

In this work, new films containing composite materials based on blends of thermoplastic polymers of the polyurethane (TPU) and polyolefin (TPO) type, in the absence and presence of BaTiO3 nanoparticles (NPs) with the size smaller 100 nm, were prepared. The vibrational properties of the free films depending on the weight ratio of the two thermoplastic polymers were studied. Our results demonstrate that these films are optically active, with strong, broad, and adjustable photoluminescence by varying the amount of TPU. The crystalline structure of BaTiO3 and the influence of thermoplastic polymers on the crystallization process of these inorganic NPs were determined by X-ray diffraction (XRD) studies. The vibrational changes induced in the thermoplastic polymer’s matrix of the BaTiO3 NPs were showcased by Raman scattering and FTIR spectroscopy. The incorporation of BaTiO3 NPs in the matrix of thermoplastic elastomers revealed the shift dependence of the photoluminescence (PL) band depending on the BaTiO3 NP concentration, which was capable of covering a wide visible spectral range. The dependencies of the dielectric relaxation phenomena with the weight of BaTiO3 NPs in thermoplastic polymers blends were also demonstrated.

Development of a simple method for determination of gas permeability resistance of whole chemical protective gloves

Objectives: We investigated the protection performance of whole gloves by developing a straightforward permeability resistance method and evaluating the permeation over 480 min. Methods: The permeation time for toluene was obtained for seven glove types according to the Japanese Industrial Standards. In addition, the permeability resistance of whole gloves was evaluated from the ratio of collected amount of toluene in the passive layered sampler attached to the inside and outside of the glove. Results: The permeation times of the two types of polyurethane gloves evaluated were less than 1 min each. However, the percentages of toluene that permeated through the whole gloves determined by the developed method were 32.5% and 6.8% for the thin and thick gloves, respectively, at 480 min and 71.8% and 24.1% for the thin and thick gloves, respectively, at 1,440 min. Permeation times for all three types of layered films were more than 1,440 min, but the whole glove tests showed differences of 1.7%, 3.1%, and less than 0.1% at 1,440 min. The causes of these differences were assumed to be related to variations in thickness, type of material, and differences in deposition state of the various gloves. Conclusions: It became possible to grasp the permeation performance throughout whole chemical resistant gloves, which could not be known only with material testing, using a straightforward permeability test method.

Relationship between Photoelasticity of Polyurethane and Dielectric Anisotropy of Diisocyanate, and Application of High-Photoelasticity Polyurethane to Tactile Sensor for Robot Hands.

Eight types of polyurethane were synthesized using seven types of diisocyanate. It was found that the elasto-optical constant depends on the concentration of diisocyanate groups in a unit volume of a polymer and the magnitude of anisotropy of the dielectric constant of diisocyanate groups. It was also found that incident light scattered when bending stress was generated inside photoelastic polyurethanes. A high sensitive tactile sensor for robot hands was devised using one of the developed polyurethanes with high photoelasticity.