New thermal deblocking characterisation method of aqueous blocked polyurethane

2014 ◽  
Vol 43 (4) ◽  
pp. 194-200 ◽  
Author(s):  
Yanhua Zhang ◽  
Jun Cao ◽  
Haiyan Tan ◽  
Jiyou Gu
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Wood Adhesive ◽  
Infrared Spectrometry ◽  
Particle Analysis ◽  
Average Particle ◽  
Content Type ◽  
Wood Processing ◽  
Blocking Rate ◽  
Blocked Isocyanate

Purpose – The mechanisms of the deblocking reaction of the polyurethane with blocking agent were investigated in detail relatively using thermogravimetric analysis (TGA), Fourier transform infrared spectrometry (FTIR) and X-ray photoelectron spectroscopy (XPS). This kind of method for polyurethane as the application of wood adhesives can provide the conditions of application and the main theoretical basis. Design/methodology/approach – The blocking rate and latex particle size distribution were determined using the titrimetric analysis and the laser particle analysis, respectively. TGA, FTIR, XPS and differential scanning calorimetry were used to investigate the deblocking temperature and time of the blocked isocyanate in detail. Findings – The results indicated that the blocking rate was approximately 97 per cent and the average particle size was 360 nm. The results of laser particle analysis have confirmed that the dispersivity of the blocked polyurethane emulsion was good. XPS results showed that the amount of –O = C-N-benzyl groups increased with an increasing deblocking temperature and subsequently reached equilibrium. In summary, the blocked isocyanate was deblocked at temperatures ranging from 50 to 90°C. Research limitations/implications – An important approach in future wood adhesive work would be to gain access to man-made board application data. Practical implications – The paper provided some useful information about deblocking mechanisms of blocked polyurethane that would be helpful to guide applied practical applications as wood adhesive. Social implications – To promote China’s wood processing technology progress and solve the problem of shortage of the natural quality of wood is of important practical significance. Originality/value – The paper is the first to use the XPS characterisation method to characterise deblocking polyurethane solution.

Synthesis and properties of novel self-crosslinked cationic fluorinated acrylic latex prepared with novel emulsified system

2016 ◽  
Vol 45 (4) ◽  
pp. 259-264
Author(s):  
Wen Li ◽  
Zhongbin Bao ◽  
Lijun Chen ◽  
Dongshun Deng
Keyword(s):  
Particle Size ◽  
Gemini Surfactants ◽  
Average Particle Size ◽  
Water Soluble ◽  
Average Particle ◽  
Mixed Surfactants ◽  
The Novel ◽  
Content Type ◽  
Acrylic Latex ◽  
Emulsion Polymerisation

Purpose At present, the conventional method of preparing cationic fluorinated acrylic latex is to emulsify copolymerised monomers with cationic surfactants. However, there has been a wide concern about using Gemini surfactants to prepare cationic polymer latex to improve its properties. The purpose of this paper was to focus on the synthesis of novel self-crosslinked cationic fluorinated acrylic latex (SCFAL), during which the copolymerised monomers were initiated with a water soluble azo initiator and emulsified with mixed surfactants of Gemini emulsifier and alkyl polyglycoside (APG). Design/methodology/approach The novel SCFAL was prepared successfully by the semi-continuous seeded emulsion polymerisation of butyl acrylate, methyl methacrylate, hexafluorobutyl methacrylate (HFMA) and hydroxy propyl methacrylate (HPMA) in aqueous medium. Findings The conversion is the maximum and the coagulation percentage the minimum when the amounts of emulsifier and initiator are 8 and 0.6 per cent, respectively. The average particle size of the latex is significantly reduced with the increase of the amount of emulsifiers used. However, the average particle size of the latex is increased with the increase of the amount of HPMA. The particle size of the latex is of a unimodal distribution, which means that the particle size was reasonably uniform. Contact angle is increased with the increase of the amount of the HFMA. Practical implications The novel SCFAL can be widely used as significant components in the field of coatings, leather, textile, paper, adhesives and so on. Originality/value SCFAL, which was emulsified with novel mixed surfactants of Gemini surfactant and APG, has been prepared successfully. Influences of amount of initiator, emulsifier, HPMA and HFMA on emulsion polymerisation and/or properties of novel latex are investigated in detail.

Slurry erosion performance study of HVFS sprayed Ni-20Al2O3 and Ni-15Al2O3-5TiO2 coatings under hydro accelerated conditions

2018 ◽  
Vol 70 (4) ◽  
pp. 805-817 ◽  
Author(s):  
Rajeev Kumar ◽  
Sanjeev Bhandari ◽  
Atul Goyal ◽  
Yogesh Kumar Singla
Keyword(s):  
Particle Size ◽  
Rotational Speed ◽  
Average Particle Size ◽  
Synergetic Effect ◽  
Average Particle ◽  
Flame Spray ◽  
Slurry Erosion ◽  
Content Type ◽  
Slurry Concentration ◽  
Ca6nm Steel

Purpose This paper aims to cover all the aspects of development, investigation and analysis phases to evaluate the slurry erosion performance of test coatings. The powders having composition of Ni-20Al2O3 and Ni-15Al2O3-5TiO2 were deposited on CA6NM grade turbine steel by using high velocity flame spray (HVFS) technique. The characterization of the coatings was done with the help of SEM/EDS and XRD techniques. Various properties such as micro-hardness and bonding strength of the coatings were also evaluated. Thereafter, these coatings were subjected to an indigenously developed high speed slurry erosion tester at different levels of rotational speed, erodent particle size and slurry concentration. The effect of these parameters on the erosion behavior of coatings was also evaluated. The slurry erosion tests and SEM of the eroded surfaces revealed remarkable improvement in slurry erosion resistance of Ni-15Al2O3-5TiO2 coating in comparison with Ni-20Al2O3 coating. Design/methodology/approach Two different compositions of HVFS coating were developed onto CA6NM steel. Subsequently, these coatings were evaluated by means of mechanical and microstructural characterization. Further, slurry erosion testing was done to analyze the erosive wear behavior of developed coatings. Findings The coatings were successfully developed by HVFS process. Cross-sectional microscopic analysis of sprayed coatings revealed a continuous and defect-free contact between substrate and coating. Ni-15Al2O3-5TiO2 coating showed higher value of bond strength in comparison with Ni-20Al2O3 coating. Under all the testing conditions, Ni-15Al2O3-5TiO2 coatings showed higher resistance to slurry erosion in comparison with Ni-20Al2O3 coatings. Rotational speed, average particle size of erodent and slurry concentration were found to have proportional effect on specific mass loss of coatings. The mixed behavior (brittle as well as ductile) of the material removal mechanism was observed for the coatings. Originality/value From the literature review, it was found that researchers have documented the various studies on Ni-Al2O3, Ni-TiO2 and Al2O3-TiO2 coatings. No one has ascertained the synergetic effect of Alumina and Titania on the slurry erosion performance of Nickel-based coating. In view of this, the authors have developed Ni-Al2O3 and Ni-Al2O3-TiO2 coatings, and an attempt has been made to compare their mechanical, microstructural and slurry erosion characteristics.

Optimum formulation derivation for the ultimate packing fraction using monodispersed particle sizes when optimizing suspension viscosities

2019 ◽  
Vol 48 (1) ◽  
pp. 45-56
Author(s):  
Richard D. Sudduth
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Packing Fraction ◽  
Size Ratio ◽  
Average Particle ◽  
Particle Sizes ◽  
Monodisperse Particle ◽  
Content Type ◽  
Particle Size Ratio ◽  
Minimum Number

Purpose The importance of maximizing the particle packing fraction in a suspension by maximizing average particle size ratio of D5/D1 has been adequately shown to be important as previously reported in the literature. This study aims to extend that analysis to include the best formulation approach to maximize the packing fraction with a minimum number of monodisperse particle sizes. Design/methodology/approach An existing model previously developed by this author was modified theoretically to optimize the ratio used between consecutive monodisperse particle sizes. This process was found to apply to a broad range of particle configurations and applications. In addition, five different approaches for maximizing average particle size ratio D̅5/D̅1 were addressed for blending several different particle size distributions. Maximizing average particle size ratio D̅5/D̅1 has been found to result in an optimization of the packing fraction. Several new concepts were also introduced in the process of maximizing the packing fraction for these different approaches. Findings The critical part of the analysis to maximize the packing fraction with a minimum number of particles was the theoretical optimization of the ratio used between consecutive monodisperse particle sizes. This analysis was also found to be effectively independent of the maximum starting particle size. This study also clarified the recent incorrect claim in the literature that Furnas in 1931 was the first to generate the maximum theoretical packing fraction possible for n different particles that was actually originally developed in conjunction with the Sudduth generalized viscosity equation. In addition, the Furnas generated equation was also shown to give significantly different results from the Sudduth generated equation. Research limitations/implications Experimental data involving monodisperse particles of different blends with a minimum number of particle sizes that are truly monodisperse are often extremely difficult to obtain. However, the theoretical general concepts can still be applicable. Practical implications The expanded model presented in this article provides practical guidelines for blending pigments using a minimum number of monodisperse particle sizes that can yield much higher ratios of the particle size averages D̅5/D̅1 and thus potentially achieve significantly improved properties such as viscosity. Originality/value The model presented in this article provides the first apparent guidelines to control the blending of pigments in coatings by the optimization of the ratio used between consecutive monodisperse particle sizes. This analysis was also found to be effectively independent of the maximum starting particle size.

Preparation of thermal transfer ink using disperse fluorescent yellow 82 for polyester substrates

2014 ◽  
Vol 43 (2) ◽  
pp. 92-96 ◽  
Author(s):  
Yufei Xiu ◽  
Qiankun Shen ◽  
Fei Fan ◽  
Chaoxia Wang
Keyword(s):  
Particle Size ◽  
Image Quality ◽  
Diethylene Glycol ◽  
Ph Value ◽  
Average Particle Size ◽  
Average Particle ◽  
Polyester Fabrics ◽  
Content Type ◽  
Thermal Transfer ◽  
Line Image

Purpose – A disperse fluorescent yellow paste was mixed with a dispersant naphthalene sulfonic derivative via wet grinding process to prepare thermal transfer ink with good fluorescence. The paper aims to discuss these issues. Design/methodology/approach – The surface tension, viscosity, pH value, zeta potential, stability and the morphology of ink samples were tested after the storing process. Findings – The morphology of paste was homogeneous nearly spherical nanoparticles and the particle size was about 100 nm from the transmission electron microscopy (TEM), which was similar to the average particle size obtained from the particle size analyser. Research limitations/implications – The paste particle size was 126.8 nm after storing at 50°C for one week. The addition of diethylene glycol was conducive to high fluorescent reflectivity and gave good line image quality both in warp and weft directions due to the low viscosity. Inkjet printed polyester fabrics achieved excellent rubbing, laundering and thermal subliming fastnesses. Originality/value – The polyester fabrics thermal transferred with the ink contained diethylene glycol represented higher fluorescent reflectivity and gave better line image quality both in warp and weft directions. The inkjet printed polyester fabrics showed excellent colour reproducibility and all the fastnesses, including rubbing, laundering and thermal subliming, were higher than Grade 4.

Effect of diisocyanates on the structure and properties of UV-curable polyurethane dispersions with nano-scale particles

e-Polymers ◽  
2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Yanyan Wei ◽  
Haobo Xin
Keyword(s):  
Particle Size ◽  
Average Particle Size ◽  
Molecular Structures ◽  
Hexamethylene Diisocyanate ◽  
Infrared Spectrometry ◽  
Average Particle ◽  
Mass Ratio ◽  
Uv Curable ◽  
Nano Scale ◽  
Polyurethane Dispersions

AbstractA series of anionic polyurethane prepolymers with different molecular structures were synthesized. Different amounts of hexamethylene diisocyanate (HDI) and toluence diisocyanate (TDI) were employed in the synthesis. When the carboxylic content was 0.3 mmol/g, the colloidal stability of the polyurethane dispersions was rather good and their particle size was nano-scale. Moreover, no acetone or other solvent were used during the process of emulsification. The structures of the polyurethane prepolymers were characterized by Fourier transform Infrared spectrometry with attenuated total reflectance (FTIR-ATR) and Gel permeation chromatography (GPC). It was found that the mass ratio of HDI to TDI was able to be quantitatively analyzed by means of FTIR-ATR. The molecular weight and distribution did not show a regular trend with the changing of HDI/TDI ratio. The influence of diisocyanate on the particle size and the coating properties was investigated. It seems that hexamethylene diisocyanate was helpful for obtaining nano-scale particles. These polyurethane dispersions could obtain an average particle size less than 100 nm when mass ratio of HDI/TDI was above 0.25. The polyurethane dispersions with nano-scale particle had a transparent appearance with a bluish cast. It is indicated that the hydrophilic efficiency would be improved and the coating hardness decreased if more HDI was employed.

scholarly journals BETAMETHASONE DIPROPIONATE GEL FOR TREATMENT OF LOCALIZED PLAQUE PSORIASIS

2017 ◽  
Vol 9 (8) ◽  
pp. 173 ◽  
Author(s):  
Sanaa El Gizaway ◽  
Maha Fadel ◽  
Basma Mourad ◽  
Fatma El-zahraa Abd Elnaby
Keyword(s):  
Particle Size ◽  
Drug Release ◽  
Average Particle Size ◽  
Entrapment Efficiency ◽  
Betamethasone Dipropionate ◽  
Average Particle ◽  
Topical Formulation ◽  
Content Type ◽  
Drug Content

Objective: The main aim of this study was to design and characterise betamethasone di-propionate loaded transfersomes (BD-T); as a topical formulation for the treatment of localized plaque psoriasis.Methods: A full factorial design (23) was applied to study the effects of three independent variables: drug content, type of surfactants and surfactant contents on particle size (PS), entrapment efficiency (EE %), zeta potential (ZP), polydispersity index (PI) and drug release profiles. The optimized BD-T was formulated as a hydrogel using 5% sodium carboxymethyl cellulose. The gel was characterized for viscosity, drug content, in vitro drug release and stability. A comparative clinical study was performed on 20 patients with psoriasis to investigate the effect of BD-T gel and the marketed betamethasone dipropionate (BD) cream.Results: The optimized BD-T formulation containing 50 mg betamethasone dipropionate (BD) and 5 mg tween 80 showed spherical unilamellar vesicles with an average particle size of 242.80, % EE of 90.19%, ZP of-15.00 mV, PI of 0.407 and K0 of 4.290 mg/hr. The formulation showed good stability at 4 °C and 25 °C for 6 mo. The results revealed significant clinical improvement and a significant increase in safety and tolerability with BD-T gel compared with BD cream.Conclusion: As a conclusion, BD-T was found to be more effective, safe and tolerable for the treatment of psoriasis compared with the marketed product.

scholarly journals Synthesis, Property and Mechanism Analysis of a Novel Polyhydroxy Organic Amine Shale Hydration Inhibitor

Minerals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 128 ◽  
Author(s):  
Weichao Du ◽  
Xiangyun Wang ◽  
Gang Chen ◽  
Jie Zhang ◽  
Michal Slaný
Keyword(s):  
Particle Size ◽  
Linear Expansion ◽  
Average Particle Size ◽  
Wellbore Stability ◽  
Inhibition Mechanism ◽  
Infrared Spectrometry ◽  
Average Particle ◽  
Mechanism Analysis ◽  
Organic Amine ◽  
Inhibition Performance

Based on the adsorption mechanism analysis of polyhydroxy organic compound on a shale surface, a novel polyhydroxy organic amine shale hydration inhibitor N, N, N′, N′-tetrakis (2-hydroxyethyl) ethylenediamine (THEED) was synthesized via a nucleophilic reaction by using diethanolamine and dibromoethane as raw materials. Its structure was characterized by Fourier transform infrared spectrometry (FTIR), Hydrogen Nuclear Magnetic Resonance (1H NMR) and Liquid Chromatography Mass Spectrometry (LCMS). The inhibition performance of THEED was studied by a shale rolling recovery experiment, a linear expansion experiment and the particle size distribution experiment. Results showed the shale rolling recovery rate in 2.0 wt % THEED solutions was up to 89.6% at the rolling condition of 100 °C × 16 h, and the linear expansion height of artificial shale core in 2.0 wt % THEED solutions was just 4.74 mm after 16 h. The average particle size of Na-bentonite (Na-MMT) in fresh water was 8.05 μm, and it was observed that the average particle size has been increased to 124 μm in 2.0 wt % THEED solutions. The shale hydration inhibition mechanism of the novel inhibitor THEED was analyzed by FTIR, Scanning Electron Microscopy (SEM) and X-ray diffractometry (XRD), we concluded that the nice shale hydration inhibition performance of THEED was achieved by means of intercalation and adsorption onto the surface of shale. The superior shale hydration inhibition property makes THEED promising in maintaining wellbore stability in drilling engineering.

Preparation and characterization of palm oil in water microemulsion for application in the food industry

2020 ◽  
Vol 122 (10) ◽  
pp. 3077-3088
Author(s):  
Parichehr Fatehi ◽  
Ahmad Salihin Baba ◽  
Vicit Rizal Eh suk ◽  
Misni Misran
Keyword(s):  
Particle Size ◽  
Vitamin E ◽  
Palm Oil ◽  
Food Industry ◽  
Room Temperature ◽  
Average Particle Size ◽  
Average Particle ◽  
Content Type ◽  
Oil In Water ◽  
Span 60

PurposeRed palm oil contains both tocopherol (∼30%) and tocotrienol (∼70%) with the latter having better antioxidant potency than the former by a factor of 60 times. The microemulsion is one of the most suitable carriers to protect this vitamin E from environmental stress due to food processing and storage. However, the instability of microemulsion might limit the presentation of vitamin E in the food industry. In the present study, we demonstrated the preparation of microemulsions from different ratios of palm oil and Span 60 to achieve potential carrier formulations for vitamin E delivery.Design/methodology/approachThe microemulsions with the different ratios of palm oil and water (o/w) and Span 60 were prepared by using homogenization technique, incubated and observed at 45.0 ± 0.1 °C, room temperature (25 °C ± 0.1) or 8.0 ± 0.1 °C. The microemulsion formed was analyzed by Fourier transforms infrared (FTIR) spectroscopy to observe the molecular composition and the functional groups in the employed oil and emulsifier. Back-scattered dynamic light scattering (DLS) method was employed to determine the stability of microemulsion by measuring the average particle size and polydispersity index (PDI). The zeta potential values of microemulsion were measured by Shape Zeta sizer Nano ZS. The shape and dynamic properties of the microemulsion were observed by Leica optical polarizing microscope (OPM). The creaming, sedimentation, the ratio of aqueous separation and clarification of the microemulsions were evaluated visually whereas the changes in pH were determined using pH meter.FindingsThe morphological study showed the presence of spherical-shaped particles. The average particle size was found to be the smallest in the presence of 7% Span 60 in the 70/30 (o/w) formulation, and the zeta potential was less than −30 mV for most of the formulations. The most stable pH (the least amount of changes in the pH at room temperature) prevailed for 7% Span 60. Accelerated stability test showed that formulations 30:70 and 50:50 (o/w), in the presence of 5% and 7% Span 60, were the most stable throughout the incubation period.Originality/valueThe palm oil in water microemulsion in the presence of 7% Span 60 has the potential to be further developed as a delivery system for hydrophobic nutrients such as vitamin E, proteins or peptides and antioxidants in the food and beverage industry.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

Formulating SLN and NLC as Innovative Drug Delivery Systems for Non-Invasive Routes of Drug Administration

2020 ◽  
Vol 27 (22) ◽  
pp. 3623-3656 ◽  
Author(s):  
Bruno Fonseca-Santos ◽  
Patrícia Bento Silva ◽  
Roberta Balansin Rigon ◽  
Mariana Rillo Sato ◽  
Marlus Chorilli
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Drug Release ◽  
Drug Loading ◽  
Average Particle Size ◽  
Delivery Systems ◽  
Average Particle ◽  
Minor Importance ◽  
Routes Of Administration ◽  
Non Invasive

Colloidal carriers diverge depending on their composition, ability to incorporate drugs and applicability, but the common feature is the small average particle size. Among the carriers with the potential nanostructured drug delivery application there are SLN and NLC. These nanostructured systems consist of complex lipids and highly purified mixtures of glycerides having varying particle size. Also, these systems have shown physical stability, protection capacity of unstable drugs, release control ability, excellent tolerability, possibility of vectorization, and no reported production problems related to large-scale. Several production procedures can be applied to achieve high association efficiency between the bioactive and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. The whole set of unique advantages such as enhanced drug loading capacity, prevention of drug expulsion, leads to more flexibility for modulation of drug release and makes Lipid-based nanocarriers (LNCs) versatile delivery system for various routes of administration. The route of administration has a significant impact on the therapeutic outcome of a drug. Thus, the non-invasive routes, which were of minor importance as parts of drug delivery in the past, have assumed added importance drugs, proteins, peptides and biopharmaceuticals drug delivery and these include nasal, buccal, vaginal and transdermal routes. The objective of this paper is to present the state of the art concerning the application of the lipid nanocarriers designated for non-invasive routes of administration. In this manner, this review presents an innovative technological platform to develop nanostructured delivery systems with great versatility of application in non-invasive routes of administration and targeting drug release.

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