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Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6284
Author(s):  
Michał Tomczak ◽  
Jakub Łopiński ◽  
Agnieszka Kowalczyk ◽  
Krzysztof Kowalczyk

A thermoplastic intumescent coating system (IC) based on poly(vinyl acetate) was modified by two forms of multiwalled carbon nanotubes (CNTs), i.e., by a nanofiller powder and its solid dispersions in pentaerythritol (PER-CNTs). It was revealed that only the PER-CNTs modifier allows us to obtain solvent-borne ICs with a relatively high CNTs concentration (1–3 wt. parts of CNTs/100 wt. parts of paint solids) and acceptable application viscosity. Thermal insulation time (TIT) and intumescent factor (IF) of the ICs on a steel substrate (a fire test according to a cellulosic fire curve), as well as morphology, chemical structure (by the FT-IR technique) and mechanical strength of the charred systems, were investigated. It was found that the CNTs powder decreases TIT and IF values while PER-occluded CNTs improve these parameters (e.g., +4.6 min and +102% vs. an unmodified sample, respectively). Compressive strength of the charred ICs was improved by the PER-CNTs modifier as well.


Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3473
Author(s):  
Jordan T. Sutton ◽  
Kalavathy Rajan ◽  
David P. Harper ◽  
Stephen C. Chmely

Despite recent successes in incorporating lignin into photoactive resins, lignin photo-properties can be detrimental to its application in UV-curable photopolymers, especially in specialized engineered resins for use in stereolithography printing. We report on chemical modification techniques employed to reduce UV absorption by lignin and the resulting mechanical, thermal, and cure properties of these modified lignin materials. Lignin was modified using reduction and acylation reactions and incorporated into a 3D printable resin formulation. UV–Vis absorption at the 3D printing range of 405 nm was reduced in all modified lignins compared to the unmodified sample by 25% to ≥ 60%. Resins made with the modified lignins showed an increase in stiffness and strength with lower thermal stability. Studying these techniques is an important step in developing lignin for use in UV-curing applications and further the effort to valorize lignin towards commercial use.


2021 ◽  
Vol 11 (10) ◽  
pp. 4372
Author(s):  
Sergey G. Anikeev ◽  
Anastasiia V. Shabalina ◽  
Sergei A. Kulinich ◽  
Nadezhda V. Artyukhova ◽  
Daria R. Korsakova ◽  
...  

A new approach to fabricate TiNi surfaces combining the advantages of both monolithic and porous materials for implants is used in this work. New materials were obtained by depositing a porous TiNi powder onto monolithic TiNi plates followed by sintering at 1200 °C. Then, further modification of the material surface with a high-current-pulsed electron beam (HCPEB) was carried out. Three materials obtained (one after sintering and two after subsequent beam treatment by 30 pulses with different pulse energy) were studied by XRD, SEM, EDX, surface profilometry, and by means of electrochemical measurements, including OCP and EIS. Structural and compositional changes caused by HCPEB treatment were investigated. Surface properties of the samples during their storage in saline for 10 days were studied and a model experiment with cell growth (MCF-7) was carried out for the unmodified sample with an electron beam to detect cell appearance on different surface locations.


2019 ◽  
Vol 15 (4) ◽  
pp. 528-531
Author(s):  
Norhidayah Abdul Hassan ◽  
Nur Azni Ruzi ◽  
Nurul Athma Mohd Shukry ◽  
Ramadhansyah Putra Jaya ◽  
Mohd Rosli Hainin ◽  
...  

The addition of modifier, either to replace bitumen or as an additive, could potentially improve the performance of conventional bitumen used in road construction. This study characterizes the physical properties of bitumen 80/100 penetration grade modified with diatomite powder and waste engine oil (WEO). Different percentages of WEO i.e. 1%, 2%, and 3%, were added with 1% diatomite to the bitumen. The conventional and modified bitumen samples were tested for penetration, softening point, viscosity, and loss on heating. Results showed that the increase of WEO content, particularly at 3% in the modified bitumen, has softened the bitumen with lower softening point and higher loss on heating than the unmodified sample. In contrast, the diatomite powder has shown potential in reinforcing the bitumen structure at high temperature based on higher viscosity obtained at 165°C compared to conventional bitumen.


2014 ◽  
Vol 1061-1062 ◽  
pp. 262-266
Author(s):  
Yi Ma ◽  
Wen Bin Liang ◽  
Yin Ling Zhang

In this study, reactive processing of maleated polypropylene with different types of amine modifiers, including 1,12-diaminododecane, tetraethylenepentamine, p-phenylenediamine, and 1,6-diaminlhexane were carried out. The changes in melt viscosity, molecular weight and its distribution, as well as crystallization were measured and discussed. All the modified samples exhibited increased molecular weight and enhanced branching structure compared to the virgin maleated PP. Aniline modified sample exhibited the highest weight average molar mass., while polyamide-modified maleated PP showed the highest degree of branching. It was also noted that all of the amine-modified samples showed higher crystallization and melting temperatures than that of the unmodified sample.


2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Alfonso Pozio

This work is intended to define a new possible methodology for the TiO2doping through the use of an electrochemical deposition of cobalt directly on the titanium nanotubes obtained by a previous galvanostatic anodization treatment in an ethylene glycol solution. This method does not seem to cause any influence on the nanotube structure, showing final products with news and interesting features with respect to the unmodified sample. Together with an unmodified photoconversion efficiency under UV light, the cobalt doped specimen reports an increase of the electrocatalytic efficiency for the oxygen evolution reaction (OER).


2013 ◽  
Vol 724-725 ◽  
pp. 1029-1032 ◽  
Author(s):  
Qing Lin He ◽  
Feng Gao ◽  
Hong Zhang Song ◽  
Xing Hu

The electric resistivity, Seebeck coefficients and power factors of Y1-xEuxBaCo4O7+δ(x = 0.0, 0.05, 0.1, 0.2) ceramics were investigated from 400K to 1000K. The results show that the presence of Eu decreases electrical resistivity, and has little effect on Seebeck coefficients of the samples. The activation energy of conductivity is calculated by the Arrhenius plots in the semiconductive region. According to power factors, the optimum Eu substitution amount is x = 0.1, which results in a higher power factor of 67.5 μWm-1K-2at 1000K, 30% higher than unmodified sample YBaCo4O7+δ.


2011 ◽  
Vol 236-238 ◽  
pp. 1410-1414 ◽  
Author(s):  
Xiao Juan Jin ◽  
Wu Yu ◽  
Zhi Ming Yu

lignin (L)-based phenolic prepolymers with different phenol (P) substitution degrees were synthesized using the modified(M) L with laccase. It was found that the ML showed lower molecular value, polydispersity and higher reactivity compared to unmodified sample, and up to 30% of phenol can be substituted by MF to give LPF wood adhesive having better bonding strength in comparison to a control unmodified lignin phenol formaldehyde wood adhesive. MF was characterized using FTIR and GPC. FTIR showed that after the treatment of laccase, the methoxyl group increased, which was mainly due to the demethylation, and laccase/mediator system made the ether bonds of L cleave to produce more alcohol hydroxyl, as a result, the reactivity of ML was improved.


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