Synthesis, modification, and characterization of organosilicone and acrylate copolymer latex

2011 ◽  
Vol 31 (4) ◽  
Author(s):  
Lei Xu ◽  
Chun-hua Dai ◽  
Lei Chen ◽  
Hong-de Xie
Keyword(s):  
Particle Size ◽  
Silicon Content ◽  
Gas Permeability ◽  
Chemical Properties ◽  
Fire Retardant ◽  
High Energy ◽  
Latex Film ◽  
Drawing Rate ◽  
Acrylic Latex ◽  
Acrylate Copolymer

Abstract Silicone elastomers are well known for their interesting physical and chemical properties such as low surface tension and surface energy, high energy of Si–O bond, good molecule flexibility, increased modulus, decreased thermal expansion coefficient, increased heat distortion temperature, reduced gas permeability, better fire-retardant properties, enhanced ionic conductivity, low flammability, increased solvent resistance, lower material cost, and ease of preparation and processing. High-silicon-content silicone-acrylate copolymerization emulsion by octamethylcyclotetrasiloxane (D4) and acrylic ester was synthesized and characterized in this article. About 20 wt% silicon content gave the latex film a rubberlike characteristic as shown by the study of the resilience and tensile curve of the silicone-acrylic latex film. The emulsions were characterized using Fourier transform infrared spectroscopy. A Mastersizer 2000 particle size distributor from Malvern Instruments was used to measure the particle size distribution of the organosilicone-acrylate copolymer emulsion. In this article, the thermal properties of the copolymers were studied using thermogravimetric analysis. The morphology structure of the latex film was determined by transmission electron microscopy. The analysis results indicated that the latex film presented high drawing rate and high elasticity. Compared with common polymer fluid, the latex displayed a sound performance in flowability, elastic resilience, and industry application value.

Regulation of Nanomaterials under present and future Chemicals legislation Analysis and regulative options

elni Review ◽  
2009 ◽  
pp. 31-38
Author(s):  
Stefanie Merenyi ◽  
Martin Führ ◽  
Kathleen Ordnung
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Automobile Industry ◽  
Small Particle ◽  
Chemical Properties ◽  
Active Surface ◽  
High Energy ◽  
Small Particle Size ◽  
White Pigment ◽  
Negative Results

Nanotechnology has already entered our everyday life. It finds application in a large number of industrial areas, for instance in the automobile industry, in energy and environmental technology, mechanical engineering, the chemicals and pharmaceuticals industry, in medicine, cosmetics and the food industry. Nanoscale titanium dioxide in sunscreen products, for example, provides UV protection, car tyres contain – not only recently – nanoscale carbon black, and many scratchproof, antireflection, non-stick and de-misting surfaces are manufactured with the help of nanomaterials. What distinguishes nanomaterials from previously used substances and processes is, above all, their large and active surface in proportion to their volume. The small particle size can result in modified chemical properties and functionalities compared to conventional substance in a non-nanoscale form, which can range from varied melting and boiling points to greater hardness, magnetism and catalytic effects. Nanotechnology is regarded as a key technology of the 21st century. Considerable economic expectations are attached to its further development. Due to its low consumption of resources and high energy efficiency, nanotechnology also offers potential ecological relief that should be exploited. At the same time, little is presently known about risks to human health and the environment associated with nanotechnology. The modified properties of nanoscale substances can lead to different risk assessment compared to conventional materials. Early knowledge in this respect has been available for some time. As far as titanium dioxide is concerned, the suspicion has been confirmed: This material, which has been manufactured and used as white pigment for many years, was regarded as unproblematic before its appearance in this small particle size, since tests carried out with non-nanoscale particles were negative. Results of tests on titanium dioxide in the nanoscale form showed, however, that these particles could have ecotoxic effects. In view of this conflict between expected benefits and potential risks, the question arises as to which legal requirements nanotechnology is subject to. In the spring of 2006 the Federal Environmental Agency commissioned a legal appraisal of the present framework of environmental legislation with regard to nanotechnologies and the drawing up of proposals for initial action should regulatory gaps be identified. The main focus of this analysis was chemicals law, and its findings are presented in this article.

Development and Ex-vivo Evaluation of Topiramate Mucoadhesive Nanoparticles for Intranasal Delivery

2020 ◽  
Vol 13 (6) ◽  
pp. 5250-5255
Author(s):  
Ashwin Kumar Tulasi ◽  
Anil Goud Kandhula ◽  
Ravi Krishna Velupula
Keyword(s):  
Particle Size ◽  
Nasal Mucosa ◽  
Intranasal Administration ◽  
Ex Vivo ◽  
Chemical Properties ◽  
Brain Targeting ◽  
Oral Tablet ◽  
Promising Alternative ◽  
Ex Vivo Permeation

Topiramate is a second-generation antiepileptic drug used in partial, generalized seizures as an oral tablet. Oral route of administration is most convenient but shows delayed absorption. Moreover, in emergency cases, parenteral administration is not possible as it requires medical assistance. Hence, the present study was aimed to develop topiramate mucoadhesive nanoparticles for intranasal administration using ionotropic gelation method. The developed nanoparticles were evaluated for physico-chemical properties like particle size, zeta potential, surface morphology, drug content, entrapment efficiency, in vitro drug release, mucoadhesive strength, and ex vivo permeation studies in excised porcine nasal mucosa. Optimized nanoparticle formulation (T9) was composed oil mucoadhesive agent (Chitosan 1% w/w), cross linking polymer (TPP) and topiramate 275mg, 100mg and 4% respectively. It showed particle size of 350nm, high encapsulation efficacy and strong mucoadhesive strength. In vitro drug diffusion of optimized formulation showed 95.12% release of drug after 180min. Ex-vivo permeation of drug across nasal mucosa was   88.05 % after 180min. Nasocilial toxicity studies showed optimized formulation did not damage the nasal mucosa. Thus, the intranasal administration of topiramate using chitosan can be a promising alternative for brain targeting and the treatment of epilepsy.

scholarly journals Tracking Hydroplasticization by DSC: Movement of Water Domains Bound to Poly(Meth)Acrylates during Latex Film Formation

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2500
Author(s):  
Sebastian M. Dron ◽  
Maria Paulis
Keyword(s):  
Itaconic Acid ◽  
Water Resistance ◽  
Film Formation ◽  
Latex Film ◽  
Water Molecules ◽  
Acrylate Copolymer ◽  
Volatile Organic ◽  
Minimum Film Formation Temperature ◽  
Latex Film Formation ◽  
Formation Step

The film formation step of latexes constitutes one of the challenges of these environmentally friendly waterborne polymers, as the high glass transition (TG) polymers needed to produce hard films to be used as coatings will not produce coherent films at low temperature. This issue has been dealt by the use of temporary plasticizers added with the objective to reduce the TG of the polymers during film formation, while being released to the atmosphere afterwards. The main problem of these temporary plasticizers is their volatile organic nature, which is not recommended for the environment. Therefore, different strategies have been proposed to overcome their massive use. One of them is the use of hydroplasticization, as water, abundant in latexes, can effectively act as plasticizer for certain types of polymers. In this work, the effect of three different grafted hydroplasticizers has been checked in a (meth)acrylate copolymer, concluding that itaconic acid showed the best performance as seen by its low minimum film-formation temperature, just slightly modified water resistance and better mechanical properties of the films containing itaconic acid. Furthermore, film formation monitoring has been carried out by Differential Scanning Calorimety (DSC), showing that itaconic acid is able to retain more strongly the water molecules during the water losing process, improving its hydroplasticization capacity.

scholarly journals Analysis of Shielding Performance of Radiation-Shielding Materials According to Particle Size and Clustering Effects

2021 ◽  
Vol 11 (9) ◽  
pp. 4010
Author(s):  
Seon-Chil Kim
Keyword(s):  
Particle Size ◽  
Polymer Material ◽  
Energy Region ◽  
High Energy ◽  
Radiation Shielding ◽  
High Energy Region ◽  
Particle Structure ◽  
Effect Of Particle Size ◽  
Extensive Body ◽  
Shielding Material

In the field of medical radiation shielding, there is an extensive body of research on process technologies for ecofriendly shielding materials that could replace lead. In particular, the particle size and arrangement of the shielding material when blended with a polymer material affect shielding performance. In this study, we observed how the particle size of the shielding material affects shielding performance. Performance and particle structure were observed for every shielding sheet, which were fabricated by mixing microparticles and nanoparticles with a polymer material using the same process. We observed that the smaller the particle size was, the higher both the clustering and shielding effects in the high-energy region. Thus, shielding performance can be improved. In the low-dose region, the effect of particle size on shielding performance was insignificant. Moreover, the shielding sheet in which nanoparticles and microsized particles were mixed showed similar performance to that of the shielding sheet containing only microsized particles. Findings indicate that, when fabricating a shielding sheet using a polymer material, the smaller the particles in the high-energy region are, the better the shielding performance is. However, in the low-energy region, the effect of the particles is insignificant.

Astaxanthin–garlic oil nanoemulsions preparation using spontaneous microemulsification technique: optimization and their physico–chemical properties

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Seyedalireza Mortazavi Tabrizi ◽  
Afshin Javadi ◽  
Navideh Anarjan ◽  
Seyyed Javid Mortazavi Tabrizi ◽  
Hamid Mirzaei
Keyword(s):  
Antioxidant Activity ◽  
Particle Size ◽  
Subcritical Water ◽  
Chemical Properties ◽  
Polydispersity Index ◽  
Garlic Oil ◽  
Physico Chemical ◽  
Minimum Particle Size ◽  
Oil In Water ◽  
Technique Optimization

AbstractGarlic oil in water nanoemulsion was resulted through subcritical water method (temperature of 120 °C and pressure of 1.5 bar, for 2 h), using aponin, as emulsifier. Based on the prepared garlic oil nanoemulsion, astaxanthin–garlic oil nanoemulsions were prepared using spontaneous microemulsification technique. Response surface methodology was employed to evaluate the effects of independent variables namely, amount of garlic oil nanoemulsion (1–9 mL) and amount of provided astaxanthin powder (1–9 g) on particle size and polydispersity index (PDI) of the resulted nanoemulsions. Results of optimization indicated that well dispersed and spherical nanodroplets were formed in the nanoemulsions with minimum particle size (76 nm) and polydispersity index (PDI, 0.358) and maximum zeta potential value (−8.01 mV), using garlic oil nanoemulsion amount of 8.27 mL and 4.15 g of astaxanthin powder. Strong antioxidant activity (>100%) of the prepared astaxanthin–garlic oil nanoemulsion, using obtained optimum amounts of the components, could be related to the highest antioxidant activity of the colloidal astaxanthin (>100%) as compared to that of the garlic oil nanoemulsion (16.4%). However, higher bactericidal activity of the resulted nanoemulsion against Escherichia coli and Staphylococcus aureus, were related to the main sulfur bioactive components of the garlic oil in which their main functional groups were detected by Fourier transform-infrared spectroscopy.

scholarly journals Alkalinity–silicon ratio as an assessment factor for the efficiency of silicate slags in wetland rice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thoppil Sreenivasan Sandhya ◽  
Nagabovanalli Basavarajappa Prakash
Keyword(s):  
Silicon Content ◽  
Chemical Properties ◽  
Magnesium Content ◽  
Wetland Rice ◽  
Agronomic Efficiency ◽  
Economic Production ◽  
Incubation Experiments ◽  
Calcium And Magnesium ◽  
Si Content ◽  
Assessment Factor

AbstractSilicate slags are one of the most widely used silicon (Si) source in agriculture. Even though the agronomic significance of slags has been demonstrated in several crops, only a few attempts were made to evaluate these Si sources based on their chemical composition. The main objective of this study was to characterize different silicate slags based on their chemical properties and to explore the effect of these chemical properties on the yield, and Si uptake in wetland rice, and dissolution of Si into the soil. Slags were characterised for pH, calcium and magnesium content (alkalinity, A), silicon content, 5 day Na2CO3 + NH4NO3 extractable Si content, and alkalinity to Si ratio (A/Si). Greenhouse and incubation experiments were also conducted using different silicate slags and wollastonite applied at the rate of 300 kg Si ha−1. Slags with A/Si < 3 were found to be ideal Si sources for the economic production of wetland rice and found consistent in increasing soil Si content and rice Si uptake. We conclude that the A/Si ratio of slags can be used as an important parameter to assess the agronomic efficiency of silicate slags in wetland rice.

Preparation of Ginger Oil in Water Nanoemulsion Using Phase Inversion Composition Technique: Effects of Stirring and Water Addition Rates on their Physico-Chemical Properties and Stability

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Ashraf Farshbaf-Sadigh ◽  
Hoda Jafarizadeh-Malmiri ◽  
Navideh Anarjan ◽  
Yahya Najian
Keyword(s):  
Particle Size ◽  
Phase Inversion ◽  
Antimicrobial Properties ◽  
Chemical Properties ◽  
Water Addition ◽  
Chromatography Method ◽  
Stirring Rate ◽  
Physico Chemical ◽  
Oil In Water ◽  
Addition Rate

Abstract Ginger oil in water (O/W) nanoemulsions, were produced using phase inversion composition method and Tween 80, as emulsifier. Effects of processing parameters namely, stirring rate (100 to1000 rpm) and water addition rate (1–10 mL/min) were evaluated on the physico-chemical, morphological, antioxidant and antimicrobial properties of the prepared O/W nanoemulsions using response surface methodology (RSM). Results indicated that well dispersed and spherical ginger nanodroplets were formed in the nanoemulsions with minimum particle size (8.80 nm) and polydispersity index (PDI, 0.285) and maximum zeta potential value (−9.15 mV), using stirring rate and water addition rate of 736 rpm and 8.18 mL/min, respectively. Insignificant differences between predicted and experimental values of the response variables, indicated suitability of fitted models using RSM. Mean particle size of the prepared nanoemulsion using optimum conditions were changed from 8.81 ± 1 to 9.80 ± 1 nm, during 4 weeks of storage, which revealed high stability of the resulted ginger O/W nanoemulsion. High antioxidant activity (55.4%), bactericidal (against Streptococcus mutans) and fungicidal (against Aspergillus niger) activities of the prepared nanoemulsion could be related to the presence of gingerols and shogaols, a group of phenolic alkanones, in the ginger oil, which those were detected by gas chromatography method.

scholarly journals Bismuth-213 for Targeted Radionuclide Therapy: From Atom to Bedside

Pharmaceutics ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 599
Author(s):  
Stephen Ahenkorah ◽  
Irwin Cassells ◽  
Christophe M. Deroose ◽  
Thomas Cardinaels ◽  
Andrew R. Burgoyne ◽  
...  
Keyword(s):  
Cancer Treatment ◽  
Radionuclide Therapy ◽  
Chemical Properties ◽  
High Energy ◽  
Magic Bullet ◽  
Targeted Radionuclide Therapy ◽  
Energy Photon ◽  
Normal Tissues ◽  
Preclinical And Clinical Studies ◽  
Alpha Therapy

In contrast to external high energy photon or proton therapy, targeted radionuclide therapy (TRNT) is a systemic cancer treatment allowing targeted irradiation of a primary tumor and all its metastases, resulting in less collateral damage to normal tissues. The α-emitting radionuclide bismuth-213 (213Bi) has interesting properties and can be considered as a magic bullet for TRNT. The benefits and drawbacks of targeted alpha therapy with 213Bi are discussed in this review, covering the entire chain from radionuclide production to bedside. First, the radionuclide properties and production of 225Ac and its daughter 213Bi are discussed, followed by the fundamental chemical properties of bismuth. Next, an overview of available acyclic and macrocyclic bifunctional chelators for bismuth and general considerations for designing a 213Bi-radiopharmaceutical are provided. Finally, we provide an overview of preclinical and clinical studies involving 213Bi-radiopharmaceuticals, as well as the future perspectives of this promising cancer treatment option.

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