scholarly journals Design of a Waterborne Polyurethane–Urea Ink for Direct Ink Writing 3D Printing

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3287
Author(s):  
Julen Vadillo ◽  
Izaskun Larraza ◽  
Tamara Calvo-Correas ◽  
Nagore Gabilondo ◽  
Christophe Derail ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
3D Printing ◽  
Soft Segment ◽  
Waterborne Polyurethane ◽  
Solid Content ◽  
Rheological Parameters ◽  
Good Shape ◽  
Physical Gel ◽  
Tan Δ ◽  
The Relationship

In this work, polycaprolactone–polyethylene glycol (PCL–PEG) based waterborne polyurethane–urea (WBPUU) inks have been developed for an extrusion-based 3D printing technology. The WBPUU, synthesized from an optimized ratio of hydrophobic polycaprolactone diol and hydrophilic polyethylene glycol (0.2:0.8) in the soft segment, is able to form a physical gel at low solid contents. WBPUU inks with different solid contents have been synthesized. The rheology of the prepared systems was studied and the WBPUUs were subsequently used in the printing of different pieces to demonstrate the relationship between their rheological properties and their printing viability, establishing an optimal window of compositions for the developed WBPUU based inks. The results showed that the increase in solid content results in more structured inks, presenting a higher storage modulus as well as lower tan δ values, allowing for the improvement of the ink’s shape fidelity. However, an increase in solid content also leads to an increase in the yield point and viscosity, leading to printability limitations. From among all printable systems, the WBPUU with a solid content of 32 wt% is proposed to be the more suitable ink for a successful printing performance, presenting both adequate printability and good shape fidelity, which leads to the realization of a recognizable and accurate 3D construct and an understanding of its relationship with rheological parameters.

scholarly journals Recyclable Shape-Memory Waterborne Polyurethane Films Based on Perylene Bisimide Modified Polycaprolactone Diol

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1755
Author(s):  
Kang Wei ◽  
Haitao Zhang ◽  
Jianbo Qu ◽  
Jianyong Wang ◽  
Yang Bai ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Shape Memory ◽  
Storage Stability ◽  
Microphase Separation ◽  
Soft Segment ◽  
Waterborne Polyurethane ◽  
Significant Degree ◽  
Perylene Bisimide ◽  
Good Shape

Currently, much attention is given to the functionality and recyclability of waterborne polyurethane (WPU). Herein, ε-caprolactone was used as a chain extender for grafting onto perylene bisimide (PBI) and 1,4-butanediol (BDO) via ring-opening reactions to obtain PBI-PCL and BDO- PCL. Then, two kinds of WPU, namely PBI-WPU (PWPU) and BDO-WPU (BWPU), were fabricated using PBI-PCL/polytetrahydrofuran ether glycol (PTMG) and BDO-PCL/PTMG, respectively, as mixed soft segments. The properties and appearance of PWPU and BWPU emulsions were analyzed in terms of particle size, zeta potential and TEM images, and the results showed that PWPU emulsions had uniform particle size distribution and decent storage stability. AFM and DMA results revealed that PWPU films possessed a more significant degree of microphase separation and a higher glass transition temperature (Tg) than BWPU films. The PWPU films displayed good shape-memory and mechanical properties, with tensile strength up to 58.25 MPa and elongation at break up to 1241.36%. TGA analysis indicated that PWPU films had better thermal stability than BWPU films. More importantly, the PWPU films could be dissolved in a mixed solvent of acetone/ethanol (v/v = 2:1) at room temperature. The dissolved PWPU could be dispersed in deionized water to prepare waterborne polyurethane again. After the recycling process was repeated three times, the recycled PWPU emulsion still exhibited good storage stability. The recycled PWPU films maintained their original thermal and mechanical properties. Comparing the properties of BWPU and PWPU showed that the soft segment structure had important influence on waterborne polyurethane performance. Therefore, PWPU may have great potential applications in making recycling and shape-memory coating or paint.

scholarly journals Cellulose and Graphene Based Polyurethane Nanocomposites for FDM 3D Printing: Filament Properties and Printability

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 839
Author(s):  
Izaskun Larraza ◽  
Julen Vadillo ◽  
Tamara Calvo-Correas ◽  
Alvaro Tejado ◽  
Sheila Olza ◽  
...  
Keyword(s):  
3D Printing ◽  
Biomedical Applications ◽  
Fused Deposition Modeling ◽  
Cellulose Nanofibers ◽  
Waterborne Polyurethane ◽  
Printing Process ◽  
Fused Deposition ◽  
Good Shape ◽  
Deposition Modeling ◽  
New Applications

3D printing has exponentially grown in popularity due to the personalization of each printed part it offers, making it extremely beneficial for the very demanding biomedical industry. This technique has been extensively developed and optimized and the advances that now reside in the development of new materials suitable for 3D printing, which may open the door to new applications. Fused deposition modeling (FDM) is the most commonly used 3D printing technique. However, filaments suitable for FDM must meet certain criteria for a successful printing process and thus the optimization of their properties in often necessary. The aim of this work was to prepare a flexible and printable polyurethane filament parting from a biocompatible waterborne polyurethane, which shows potential for biomedical applications. In order to improve filament properties and printability, cellulose nanofibers and graphene were employed to prepare polyurethane based nanocomposites. Prepared nanocomposite filaments showed altered properties which directly impacted their printability. Graphene containing nanocomposites presented sound enough thermal and mechanical properties for a good printing process. Moreover, these filaments were employed in FDM to obtained 3D printed parts, which showed good shape fidelity. Properties exhibited by polyurethane and graphene filaments show potential to be used in biomedical applications.

scholarly journals Rheological Parameters and Transport Characteristics of Fresh Cement Tailings Backfill Slurry in an Underground Iron Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Chi Zhang ◽  
Yu-Ye Tan ◽  
Kai Zhang ◽  
Chun-Yue Zhang ◽  
Wei-Dong Song
Keyword(s):  
Solid Content ◽  
Rheological Parameters ◽  
Flow State ◽  
Pipeline Transportation ◽  
Filling System ◽  
Iron Mine ◽  
Unclassified Tailings ◽  
Fluent Software ◽  
Resistance Loss ◽  
The Relationship

Pipeline transportation is the key component of the mine filling system. In this study, fresh cement tailing backfill (CTB) slurry made by unclassified tailings from the Daye iron mine is taken as the research object, and its rheological parameters and transport characteristics are studied via laboratory test and FLUENT software. It was found that the relationship curve of the dynamic yield stress, viscosity, and solid content (SC) of CTB slurry fits the law of the H-B model when SC varies between 60% and 68%. However, the relationship curve gradually changes to fit the Bingham mode when SC reaches up to 70%. Numerical simulation results demonstrate that when the SC of CTB slurry exceeds 65%, the static pressure at the pipeline’s outlet begins to distribute symmetrically. At this point, the slurry flow state is relatively stable, and the pipeline resistance loss is positively correlated with SC and flow rate. When SC exceeds 70%, resistance loss begins to increase significantly. The findings of this study can be used to identify the suitable transportation conditions of CTB slurry and provide the theoretical direction for the pipeline transportation design of filling systems in mines.

Synthesis and properties of CO2 copolymer-based waterborne polyurethane with high solid content

2021 ◽  
Vol 28 (7) ◽  
Author(s):  
Wenqi Xian ◽  
Jie Yuan ◽  
Zhengbin Xie ◽  
Wei Ou ◽  
Xiaoxuan Liu ◽  
...  
Keyword(s):  
Waterborne Polyurethane ◽  
Solid Content ◽  
High Solid Content ◽  
High Solid

Role of in situ added cellulose nanocrystals as rheological modulator of novel waterborne polyurethane urea for 3D-printing technology

Cellulose ◽  
2021 ◽  
Author(s):  
Julen Vadillo ◽  
Izaskun Larraza ◽  
Tamara Calvo-Correas ◽  
Nagore Gabilondo ◽  
Christophe Derail ◽  
...  
Keyword(s):  
3D Printing ◽  
Cellulose Nanocrystals ◽  
Waterborne Polyurethane ◽  
Printing Technology ◽  
3D Printing Technology

scholarly journals Effect of DMPA and Molecular Weight of Polyethylene Glycol on Water-Soluble Polyurethane

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1915 ◽  
Author(s):  
Eyob Wondu ◽  
Hyun Woo Oh ◽  
Jooheon Kim
Keyword(s):  
Molecular Weight ◽  
Contact Angle ◽  
Polyethylene Glycol ◽  
Photoelectron Spectroscopy ◽  
Water Solubility ◽  
Soft Segment ◽  
Water Soluble ◽  
Size Exclusion ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry

In this study water-soluble polyurethane (WSPU) was synthesized from isophorone diisocyanate (IPDI), and polyethylene glycol (PEG), 2-bis(hydroxymethyl) propionic acid or dimethylolpropionic acid (DMPA), butane-1,4-diol (BD), and triethylamine (TEA) using an acetone process. The water solubility was investigated by solubilizing the polymer in water and measuring the contact angle and the results indicated that water solubility and contact angle tendency were increased as the molecular weight of the soft segment decreased, the amount of emulsifier was increased, and soft segment to hard segment ratio was lower. The contact angle of samples without emulsifier was greater than 87°, while that of with emulsifier was less than 67°, indicating a shift from highly hydrophobic to hydrophilic. The WSPU was also analyzed using Fourier transform infrared spectroscopy (FT-IR) to identify the absorption of functional groups and further checked by X-ray photoelectron spectroscopy (XPS). The molecular weight of WSPU was measured using size-exclusion chromatography (SEC). The structure of the WSPU was confirmed by nuclear magnetic resonance spectroscopy (NMR). The thermal properties of WSPU were analyzed using thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

Correlation among Physico-Acoustic Properties of Boscia angustifolia and Albizia adianthifolia Wood

2020 ◽  
Vol 70 (4) ◽  
pp. 396-402
Author(s):  
Kayode Olaoye ◽  
Omolabake Okon-Akan ◽  
Olaoluwa Adegoke ◽  
A. O. Bobadoye
Keyword(s):  
Wood Species ◽  
Scientific Information ◽  
Predictor Variable ◽  
Sound Frequency ◽  
Acoustic Properties ◽  
Damping Factor ◽  
Velocity Of Sound ◽  
Tan Δ ◽  
Albizia Adianthifolia ◽  
The Relationship

Abstract Underutilization of some wood species can be largely attributed to a dearth of scientific information. Therefore, identifying the acoustic characteristics of lesser used wood species such as Boscia angustifolia and Albizia adianthifolia wood is expected to encourage their use in acoustic applications. Thus, studying their acoustic properties and the relationship among these properties will help reveal their use potential for acoustic purposes and also highlight possible predictor variable(s) for other acoustic parameters in wood acoustics. This study aimed at measuring the acoustic properties of B. angustifolia and A. adianthifolia wood and investigating the correlation among these properties. Three trees of each species were felled, and a total of 270 wood samples of 20 by 20 by 300 mm3 were collected. The samples were conditioned before acoustic measurement. The longitudinal free vibration method was adopted to measure the acoustic properties. Some of the mean acoustic results obtained for B. angustifolia and A. adianthifolia wood were 835.89 Hz, 3,657.51 m/s, 0.008, 13.59 GPa, 935.39 m4 kg−1 s−1, and 807.78 Hz, 3,542.66 m/s, 0.009, 12.65 GPa, 731.75 m4 kg−1 s−1, respectively, for fundamental sound frequency (FF), velocity of sound (V), damping factor (tan δ), specific dynamic modulus of elasticity (Es), and acoustic conversion efficiency (ACE). The correlation of FF with tan δ was negatively significant (−0.59), while it was positively significant with Es and ACE (0.99 and 0.74). This study found the two wood species suitable for making frame boards only and highlights sound frequency and velocity of sound as the major predicting acoustic variables for measuring good acoustic wood.

scholarly journals The Relationship between Dissolution Behavior and the Toxicity of Silver Nanoparticles on Zebrafish Embryos in Different Ionic Environments

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 652 ◽  
Author(s):  
Wang Lee ◽  
Eungwang Kim ◽  
Hyun-Ju Cho ◽  
Taejoon Kang ◽  
Bongsoo Kim ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Polyethylene Glycol ◽  
Zebrafish Embryo ◽  
Antibacterial Properties ◽  
Dissolution Behavior ◽  
Aquatic Environments ◽  
Zebrafish Embryos ◽  
Negative Effects ◽  
The Relationship ◽  
Water Filters

A silver nanoparticle is one of the representative engineered nanomaterials with excellent optical, electrical, antibacterial properties. Silver nanoparticles are being increasingly used for medical products, water filters, and cosmetics, etc. However, silver nanoparticles are known to cause adverse effects on the ecosystem and human health. To utilize silver nanoparticles with minimized negative effects, it is important to understand the behavior of silver nanoparticles released to the environment. In this study, we compared toxicity behaviors of citrate-stabilized silver nanoparticles with polyethylene glycol coated silver nanoparticles in two different ionic environments, which are aquatic environments for developing zebrafish embryo. Depending on the composition of the ionic environment, citrate-stabilized silver nanoparticles and polyethylene glycol coated silver nanoparticles exhibited different behaviors in dissolution, aggregation, or precipitation, which governed the toxicity of silver nanoparticles on zebrafish embryos.

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