Soft segment‐free functional polyurethane: A versatile candidate for heat‐healability, non‐dissociative mechanism, and high elongation adhesive materials

2021 ◽  
Author(s):  
Rashmi Edachery Veetil ◽  
Kunduchi Periya Vijayalakshmi ◽  
Chinthalapalli Srinivas ◽  
Dona Mathew ◽  
Santhosh Kumar Kalamblayil Sankaranarayanan
Keyword(s):  
Soft Segment ◽  
Dissociative Mechanism ◽  
High Elongation ◽  
Adhesive Materials

The Structure and Properties of UV-Curable Cationic Waterborne Polyurethane Acrylate

2015 ◽  
Vol 1090 ◽  
pp. 31-37
Author(s):  
Yi Ding Meng ◽  
Hong Wei Li
Keyword(s):  
Soft Segment ◽  
Waterborne Polyurethane ◽  
Decomposition Temperature ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Uv Curable ◽  
High Elongation ◽  
Polyurethane Dispersions ◽  
High Degree ◽  
Cationic Waterborne Polyurethane

A series of stable double-terminated UV reactive cationic waterborne polyurethane dispersions was synthesized, while the structure was confirmed by infrared spectroscopy,laser particle size analysis and free NCO root titration; modified by co-monomerhydroxyethyl acrylate with the UV radiation fast curing, the influence of hydroxyethyl acrylate proportion and the polyurethane’s nNCO/nOH(R value) to the thermal properties, mechanical properties and yellowing of the product was investigated. The investigation illustrated the UV-curable cationic waterborne polyurethaneacrylate film effectively forming a semi-interpenetrating network system to achieve rapid curing coating.The results showedthe product cured by WPU dispersion of R=1.5 mixed with equimolar HEA obtained lowyellowing, the maximum breaking strength, high elongation at break, high thermal decomposition temperature, high crystallization temperature of hard segment, low glass transition temperature of soft segment, high degree of phase separation, better overall performance.

Surface interaction of sweet potato peels (Ipomoea batata) with Cd(II) and Pb(II) ions in aqueous medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Aqueous Medium ◽  
Sweet Potato ◽  
Adsorption Process ◽  
Low Cost ◽  
Correlation Coefficients ◽  
Order Kinetic ◽  
Thermodynamic Evaluation ◽  
Dissociative Mechanism ◽  
Pseudo Second Order ◽  
Potato Peels

The removal of Cd(II) and Pb(II) ions from aqueous medium was studied using potato peels biomass. The adsorption process was evaluated using Atomic Absorption Spectrophotometer (AAS). The Vibrational band of the potato peels was studied using Fourier Transform Infrared Spectroscopy (FTIR). The adsorption process was carried out with respect to concentration, time, pH, particle size and the thermodynamic evaluation of the process was carried at temperatures of 30, 40, 50 and 60(0C), respectively. The FTIR studies revealed that the potato peels was composed of –OH, -NH, –C=N, –C=C and –C-O-C functional groups. The optimum removal was obtained at pH 8 and contact time of 20 min. The adsorption process followed Freundlich adsorption and pseudo second-order kinetic models with correlation coefficients (R2) greater than 0.900. The equilibrium adsorption capacity showed that Pb(II) ion was more adsorbed on the surface of the potato peels biomass versus Cd (II) ion (200.91 mg/g > 125.00 mg/g). The thermodynamic studies indicated endothermic, dissociative mechanism and spontaneous adsorption process. This study shows that sweet potato peels is useful as a low-cost adsorbent for the removal of Cd(II) and Pb(II) ions from aqueous medium.

scholarly journals Flexible push pneumatic actuator with high elongation

2021 ◽  
Vol 321 ◽  
pp. 112578
Author(s):  
Lukasz Fracczak ◽  
Maksym Nowak ◽  
Katarzyna Koter
Keyword(s):  
Pneumatic Actuator ◽  
High Elongation

Ballistic performance of composite structure configurations with high elongation calendered rubber layer laminated to AA5083-H112 aluminum alloy

2021 ◽  
pp. 146442072110145
Author(s):  
Hasan Kasım
Keyword(s):  
Adhesion Strength ◽  
Laminated Composite ◽  
Composite Plates ◽  
Front Face ◽  
Laminated Composite Plates ◽  
Ballistic Performance ◽  
Rubber Layer ◽  
Interface Interaction ◽  
Metal Rubber ◽  
High Elongation

This study aims to determine the ballistic performances of laminated composite plates produced with AA5083-H112 series aluminum and rubber material with high elongation capacity under impact loading. To investigate the effect of rubber compounds, two types of rubber with calendered and damping were prepared. Thanks to the surface treatment applied to the aluminum plates, the rubber–metal adhesion strength was adjusted, and four different laminated composite plate samples were prepared. Calendered rubber was used on the bullet impact surface of all samples, and damping rubber was used on the back. It has been observed that the pressure barrier created by the calendered rubber bullet on the front face provides high performance to absorb energy. A detailed study was carried out on the total thickness of laminated composite plates, the interface adhesion strength between rubber and aluminum layers, and the ballistic performance of aluminum-rubber combinations. It was concluded that the laminated composite plate’s energy absorption would increase, especially by increasing the thickness of the dumping rubber layer on the back of the aluminum sheets. In the strong metal-rubber interface interaction between the rubber and aluminum layer, the bullet is stopped before the pressure barrier is formed. The penetration depth and bulging height increase, and most of the energy are transmitted through the aluminum plate. In the weak metal-rubber interface interaction, a significant portion of the energy is absorbed by the rubber and air thanks to the pressure barrier.

scholarly journals Dependence of Power Characteristics on Savonius Rotor Segmentation

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2912
Author(s):  
Krzysztof Doerffer ◽  
Janusz Telega ◽  
Piotr Doerffer ◽  
Paulina Hercel ◽  
Andrzej Tomporowski
Keyword(s):  
High Wind ◽  
Horizontal Axis Wind Turbine ◽  
Savonius Rotor ◽  
Power Characteristics ◽  
Wind Speeds ◽  
Single Segment ◽  
High Elongation ◽  
Low Wind Speeds ◽  
Number Of Segments ◽  
Rotor Type

Savonius rotors are large and heavy because they use drag force for propulsion. This leads to a larger investment in comparison to horizontal axis wind turbine (HAWT) rotors using lift forces. A simple construction of the Savonius rotor is preferred to reduce the production effort. Therefore, it is proposed here to use single-segment rotors of high elongation. Nevertheless, this rotor type must be compared with a multi-segment rotor to prove that the simplification does not deteriorate the effectiveness. The number of segments affects the aerodynamic performance of the rotor, however, the results shown in the literature are inconsistent. The paper presents a new observation that the relation between the effectiveness of single- and multi-segment rotors depends on the wind velocity. A single-segment rotor becomes significantly more effective than a four-segment rotor at low wind speeds. At high wind speeds, the effectiveness of both rotors becomes similar.

scholarly journals Activated Ductile CFRP NSMR Strengthening

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2821
Author(s):  
Jacob Wittrup Schmidt ◽  
Christian Overgaard Christensen ◽  
Per Goltermann ◽  
José Sena-Cruz
Keyword(s):  
Failure Modes ◽  
Elastic Response ◽  
Applied Theory ◽  
Strengthening Effect ◽  
The Novel ◽  
Near Surface ◽  
Linear Elastic ◽  
Near Surface Mounted ◽  
High Elongation ◽  
Strengthened Beam

Significant strengthening of concrete structures can be obtained when using adhesively-bonded carbon fiber-reinforced polymer (CFRP) systems. Challenges related to such strengthening methods are; however, the brittle concrete delamination failure, reduced warning, and the consequent inefficient use of the CFRP. A novel ductile near-surface mounted reinforcement (NSMR) CFRP strengthening system with a high CFRP utilization is introduced in this paper. It is hypothesized that the tailored ductile enclosure wedge (EW) end anchors, in combination with low E-modulus and high elongation adhesive, can provide significant strengthening and ductility control. Five concrete T-beams were strengthened using the novel system with a CFRP rod activation stress of approximately 980 MPa. The beam responses were compared to identical epoxy-bonded NSMR strengthened and un-strengthened beams. The linear elastic response was identical to the epoxy-bonded NSMR strengthened beam. In addition, the average deflection and yielding regimes were improved by 220% and 300% (average values), respectively, with an ultimate capacity comparable to the epoxy-bonded NSMR strengthened beam. Reproducible and predictable strengthening effect seems obtainable, where a good correlation between the results and applied theory was reached. The brittle failure modes were prevented, where concrete compression failure and frontal overload anchor failure were experienced when failure was initiated.

scholarly journals Impact of Macrodiols on the Morphological Behavior of H12MDI/HDO-Based Polyurethane Elastomer

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2060
Author(s):  
Shazia Naheed ◽  
Mohammad Zuber ◽  
Mahwish Salman ◽  
Nasir Rasool ◽  
Zumaira Siddique ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Chain Length ◽  
Microphase Separation ◽  
Soft Segment ◽  
Group Identification ◽  
Degree Of Crystallinity ◽  
Polyurethane Elastomers ◽  
Hard Segments ◽  
Morphological Behavior

In this study, we evaluated the morphological behavior of polyurethane elastomers (PUEs) by modifying the soft segment chain length. This was achieved by increasing the soft segment molecular weight (Mn = 400–4000 gmol−1). In this regard, polycaprolactone diol (PCL) was selected as the soft segment, and 4,4′-cyclohexamethylene diisocyanate (H12MDI) and 1,6-hexanediol (HDO) were chosen as the hard segments. The films were prepared by curing polymer on Teflon surfaces. Fourier transform infrared spectroscopy (FTIR) was utilized for functional group identification in the prepared elastomers. FTIR peaks indicated the disappearance of −NCO and −OH groups and the formation of urethane (NHCOO) groups. The morphological behavior of the synthesized polymer samples was also elucidated using scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The AFM and SEM results indicated that the extent of microphase separation was enhanced by an increase in the molecular weight of PCL. The phase separation and degree of crystallinity of the soft and hard segments were described using X-ray diffraction (XRD). It was observed that the degree of crystallinity of the synthesized polymers increased with an increase in the soft segment’s chain length. To evaluate hydrophilicity/hydrophobicity, the contact angle was measured. A gradual increase in the contact angle with distilled water and diiodomethane (38.6°–54.9°) test liquids was observed. Moreover, the decrease in surface energy (46.95–24.45 mN/m) was also found to be inconsistent by increasing the molecular weight of polyols.

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