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Synthesis, Characterization and Application of Fluorescent Brightening Agents on Synthetic Fibers

Thesis Info

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Author

Mahwish, ,

Program

PhD

Institute

University of Karachi

City

Karachi

Province

Sindh

Country

Pakistan

Thesis Completing Year

2015

Thesis Completion Status

Completed

Subject

Chemistry

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/13281/1/Mehwish_Applied_Chemistry_2015_Univ_of_Karachi_15.6.206.docx

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727504086

Similar


Names like “Fluorescent Whitening Agents”, “Optical Brighteners” and “Optical Bleach” are all used to describe the product “Fluorescent Brightening Agents”, but the term “FBAs” is preferably used because it has been taken from Chemical Abstracts. FBA is an organic compound. Most commercially available fluorescent brighteners are stilbene based having symmetric or asymmetric structures. Symmetric compounds are derivatives of 4,4''-bis(1,3,5-triazinylamino)stilbene-2,2''-disulfonic acid prepared by the reaction of 1mole of 4,4''-diaminostilbene-2,2''-disulfonic acid with 2 mole of cyanuric chloride. Synthesis of asymmetric compounds is also more expensive than symmetric compounds that’s why asymmetric compounds never become commercially important. The change in structure will effect on solubility, substrate affinity and on other properties. In this research stilbene based FBAs were synthesized from reaction of 4,4''-diaminostilbene-2,2''-disulfonic acid with 2,4,6-trichloro-1,3,5-triazine and then substitution of different nucleophilic amines on triazine moiety yielded FBAs. Substitution of different electron donating, electron withdrawing and solubilizing groups on these nucleophilic amines has great effect on properties of FBAs. The newly synthesized FBAs were characterized by UV-Visible, IR, Mass and 1H-NMR spectral data and applied on polyamide and cotton fabrics. All FBAs were light yellow in color. The performance of these FBAs was evaluated by different fastness measurements. All FBAs showed fastness grating in the range of 4-5 that is good quality performance. The color of FBAs were characterized by color co-ordinates L*, a*, b*, which in turn provide very powerful tool of objective color measurement, practiced in a modern industrial world. 3D-QSPR technique with the help of CoMFA model was applied on our synthesized FBAs.In this research we correlate CoMFA model with the absorbtivity of FBAs. A negative correlation has been observed because FBAs had low value of absorbtivity. The reason behind that is FBAs are light colored compounds they do not form covalent linkage with the fiber as like reactive dyes. They just adsorb on the fiber that’s why they had low value of absorbtivity.
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المبحث الرابع: بعض شعراء العصر الجديد

المبحث الرابع:بعض شعراء العصر الجديد
وخلاصۃ القول أن شعراء عصر النھضۃ في الدول العربیۃ قد حرصوا عل أن یقدموا الجدید في النثر والشعر، فجددوا في الفکرۃ والأسلوب والموضوع والتصویر الأدبي ومع ھذا ظلت الأصالۃ والجودۃ الصفۃ الممیزۃ في إنتاجھم، فھناك الکثیر ممن استجابوا للدعوة إلی الشعر الحر وأقدامھم کانت ثابتة في الشعر العمودي. ومن ھؤلاء الشعراء فدوی طوقان ، نزار قباني وأدونیس وغیرھم، فقد کانوا من شعراء الشعر العمودي ولکن توجھوا إلی الشعر الحر بعد اشتھارہ وانصرفوا عن الشعر العمودي، فالجدید جذب أنظارھم وأصبحوا من أشھر شعراء الحرکۃ الجدیدۃ .
ومن أوائل الشعراء الذین تقدموا في ھذہ الساحۃ الفنیۃ نازک الملائکۃ وھي الرائدۃ، وبدر شاکر السیاب وعبدالوھاب البیاتي وبلند الحیدري من العراق، وصلاح عبدالصبور وأحمد عبدالمعطي حجازي من مصر ومحمد مصباح الفیتوري من السودان۔ وفدویٰ طوقان من فلسطین، ومحمد حسین عواد وناصر أبو حمید من المملکۃ العربیۃ السعودیۃ والکثیر من الشعراء الشباب ، ونالت حرکۃ الشعر الحر إعجاب القراء والسامعین والنقاد والأدباء. وھذہ بعض أبیات من قصیدۃ ’’ثورۃ علی الشمس‘‘ للشاعرۃ العراقیۃ (نازك الملائکۃ) یتجلی فیہ أثر انفعال الشاعرۃ في جمال الوحدۃ :
وقفت أمام الشمس صارخۃ بھا یا شمس: مثلک قلبي المتمرد
قلبي الذي جرف الحیاۃ شبابہ وسقی النجوم ضیاؤہ المتجدد
مھلاً: ولا یخدعک حزن حائر في مقلتيّ۔۔۔ و دمعۃ تتنھد!
فالحزن صورۃ ثورتي وتمردي تحت اللیالي۔۔۔ والألوھۃ تشھد
والآن سنتعرف علی بعض شعراء عصر نازك الملائکۃ وھم

بدر شاکر السیاب
ولد بدر شاکر السیاب في 25 دیسمبر 1926، فھو شاعر عراقي یعد واحداً من الشعراء المشھورین في الوطن العربي في القرن العشرین، کما یعتبرأحد مؤسسي الشعر الحر في الأدب العربي ، ویقول في أنشودۃ المطر۔
عیناك غابتا نخیل ساعۃ السحر۔
أو شرفتان راح ینأی عنھما القمر
عیناک حین تبسمان تورق الکروم
وترقص الأضواء کالأقمار في النھر
یرجّہ الجذاف وھناً ساعۃ السحر
قام بعض رواد الشعر في العراق ومنھم السیاب بمحاولات جادۃ للتخلص...

Should teens be allowed to consent for vaccines?

Teens and children will need to be vaccinated in order to achieve herd immunity against COVID-19. Most parents are eager to have their teens immunized, whereas some are hesitant. Should teens be allowed to consent to immunization even if their parents’ objects? Vaccines are safe and effective, medically recommended, and good for both the individual and the community. Inspite of these powerful arguments, the law lags behind. Most parents want their teens to be immunized. Most vaccine-hesitant parents ultimately agree to vaccination. Furthermore, teens who get COVID generally have mild cases. For now, the law in most states does not permit teens to consent to the COVID-19 vaccine without parental permission.

Linear and Quasilinear Analysis of Parallel Propagating Electromagnetic Modes

In solar wind, the charged particles like electrons, protons, and alpha particles are detected to possess anisotropies in their temperatures. This skewness in their particles distributions acts as a source of free energies to excite di erent modes. These microinstabilities are known to be responsible for checking and limiting the upper levels of anisotropies, speci cally near 1 AU, and thus explains the observations made with spacecrafts more accurately. Previously, threshold conditions for these unstable modes operative under di erent circumstances were presented as an inverse correlation between temperature anisotropy, T?=Tk, and parallel plasma beta,k. These relations were deduced on the basis of linear theory combined with observationalttings, or by simulations like Particle in Cell methods. In present study, a macroscopic quasilinear approach is adopted in which these correlations naturally emerge. A set of self-consistent quasilinear kinetic equations is formulated for dynamical temperatures and wave energy densities, separately, for homogeneous and inhomogeneous solar wind medium. The solutions of these equations are not only giving us a dynamical picture of temperatures and wave energy densities, but also con rm inverse correlation between temperature anisotropy and parallel plasma beta atnal stages of numerical solutions. A bi-Maxwellian form of particle''s distribution is assumed all the time except that temperatures of solar wind species may vary in time t. The validity of same approximation is justi ed based on theoretical and simulations studies. Firstly, we have studied right-hand polarized electromagnetic electron cyclotron instability conditioned for T?e > Tke based on core/halo components model. The time asymptotic states of core and halo electrons temperatures along with wave energy density are displayed. Marginal stability curves, separately, for core and halo electrons populations are con rmed at the saturation stages of particles trajectories in ( k; T?=Tk) phase space. Secondly, a detailed quasilinear analysis of electronsrehose mode is carried out assuming dynamical ions. This left-hand polarized electromagnetic mode becomes excited for excessive parallel temperature i.e Tke > T?e, and is important for an upper check of solar wind temperatures along the ambient magneticeld. Time history of parallel electron anisotropy regulation, variations in ions heating, and associated wave energy density saturation is shown. Final stages of numerical plots of dynamical equations are corresponded to electronrehose and electromagnetic ion cyclotron marginal stability curves. Thirdly, in quasilinear frame-work, assuming dynamical ions and electrons in an inhomogeneous solar wind medium, an interplay of electron and proton instabilities is studied. We point it out as one of the mechanisms of an outstanding issue that, the majority of data points are observed in near isotropic state in phase space for protons species. In fact, this interplay of proton-cyclotron and electron rehose instabilities is leading a counter-balancing e ect which, in turn, prevents a further progression of solar wind protons towards marginalrehose state. At the end, the spatial damping for parallel propagating modes is also looked in degenerate environments employing a linear kinetic model. Foreld free case, a comparison of skin depth is made for degenerate and non-degenerate environments in di erent relativistic regimes. The role of ambient magneticeld is also characterized for these anomalous skin e ects.