Click here for full poster.

Not the best of posters but it does provide an overview of the work I did. I was able to synthesize and purify at least one dye, called NCSU-10 that performs better than the benchmark dye for DSCs called N-719.

The new dye called NCSU-10 was called RAAP during the course of my work but is being patented under a name that reflects the name of the university where the work was carried out. In simple terms, NCSU-10 performs better because it absorbs light at longer wavelengths compared to N-719. This is because it is able to harness wavelengths that N-719 can’t as it just doesn’t absorb longer wavelengths. Proof for this is shown in the the IPCE spectra in my poster.

For those who ask me what the connection between solar cells and textiles is, i’m closing this post with an image of a working solar cell I made with NCSU-10 that resembles the College of Textiles logo.

A dye sensitized solar cell fabricated at NCSU resembling the College of Textiles logo shown on top right.

An article published by National Foods’ staff highlights results from some of our research at TRIC. Shahzad Dadabhoy from TIP made significant contributions to the work from our end.
More on Quack! Online: Technical Textile Research at TRIC.
Another article on Express Tribune: The collaboration that opened up EU for National Foods.

Luckily I came across this great tool which lists possible bonds that correspond with wave numbers which you can enter. It even has an option to perform a comprehensive search if you’re looking for a broader range of possibilities.

Spectroscopic Analysis Tool

UK surface analysis forum

The final papers weren’t as great as most candidates think they were. People made some tremendous mistakes. I’m uploading the model answer paper for the exam so you can download and see what your mistakes are. There are a lot of answers that people have written that are different from what I’ve proposed in my model answers. This model answer paper is just a guideline. I have awarded credit to any candidate who has come up with a different concept and justified it as I have justified answers in the model paper.

Fibre Science, Final Exam, Spring 2008, Question Paper

Fibre Science, Final Exam, Spring 2008, Model Answers

As a general outline numerous students weren’t able to accurately answer the question on spider silk, which I was expecting to get a high proportion of correct answers on. Some students lost a huge chunk of marks on the question related to surface modification of wool fibres. Students who suggested that felting can be reduced by changing the direction of fibres lost 5 to 8 marks.

A lot of students who attempted the bulletproof jacket section of the last question lost marks because they did not specify the construction of the jacket in terms of fabric or how the fabric would be able to prevent the bullet from causing harm to the human body. Answers on artificial lungs were generally disastrous. Except for perhaps two or three good answers people who tried to make artificial lungs did not know how they would work. Geotextiles for road lining was a safer bet but not too many people selected this option. Those who did select this were generally able to score at least three marks. Out of the entire lot, only two candidates selected clothing for dust free rooms and out of those two one candidate wrote an excellent answer.

Most students who messed up such chunky questions suffered at least one drop in grade. Marks were deducted due to additional absences as per the attendance policy but only one unfortunate soul suffered a drop in grade from B to C due to loss of 2 precious marks because of 5 absences. No one else lost a grade due to absences. An overall curving of 3 marks saved a lot of your grades but some people have still missed grades by very small margins which I couldn’t do anything to change.

It is most unfortunate that I have had to distinguish my class with grades. At the end of this course I feel that most of you have done an amazing job. Although I do feel that we could have had much more interesting discussions had you people read up before coming to class, nevertheless it’s been an amazing experience teaching  this lot. You people have stimulated my thought process on many occasions and I hope that I have been able to do the same for you and been able to enhance your understanding in the subject and left you looking for more knowledge. Some candidates may have missed out on grades by very small margins but that doesn’t mean that any of you lack in intelligence. After an entire semester with your class if anyone needs an honest recommendation based on performance in my course I would be more than happy to write one for you.

With this I wish you the very best for your results. Hope you have a great summer. I’m leaving the floor open for comments.

polyester-technology: Slides from presentation by Mr. Zainul Abideen, SDM (Product Development), Gatron Industries

Electrospinning

In the electrospinning process a high voltage is used to create an electrically charged jet of polymer solution or melt, which dries or solidifies to leave a polymer fiber. One electrode is placed into the spinning solution/melt and the other attached to a collector. Electric field is subjected to the end of a capillary tube that contains the polymer fluid held by its surface tension. This induces a charge on the surface of the liquid. Mutual charge repulsion causes a force directly opposite to the surface tension. As the intensity of the electric field is increased, the hemispherical surface of the fluid at the tip of the capillary tube elongates to form a conical shape known as the Taylor cone. With increasing field, a critical value is attained when the repulsive electrostatic force overcomes the surface tension and a charged jet of fluid is ejected from the tip of the Taylor cone. The discharged polymer solution jet undergoes a whipping process wherein the solvent evaporates, leaving behind a charged polymer fiber, which lays itself randomly on a grounded collecting metal screen. In the case of the melt the discharged jet solidifies when it travels in the air and is collected on the grounded metal screen. [http://www.che.vt.edu/Wilkes/electrospinning/electrspinning.html]

Note: To avoid confusion ignore the figure on electrospinning from the above source. Instead, here is a link to a better, and more easy to understand diagram.

Spider Silk

Here’s a link to the youtube video we saw and discussed in class showing the spinning of spider silk from the milk of genetically modified goats.

I’m posting the material on proteinic fibres, synthetic fibres and fibres for technical textiles. Here are the slides we discussed in class along with the primary reference source to study from to understand the transitions that would otherwise look like jargon to those who weren’t there in class.

Lecture 10, Protenic fibres: Hearle, Morton, Physical properties of textile fibres

Lecture 11, Synthetic fibres: Study link; Notes by MA Wilding

Lecture 12, Fibres and technical textiles

Ofcourse the course doesn’t end here. For proteinic fibres also go through the notes on proteinic fibres compiled by MA Wilding. While for synthetic fibres, apart from the notes on synthetic fibres by MA Wilding, also read Hearle’s book, physical properties of textile fibres as well as go through the synthetic section on the Macrogalleria. Specifically, at least read through the material posted on some of the main classes of polymers. For synthetics, try and note the significance of the main polymeric groups such as the Methyl, Benzene, Amide and others that were discussed in class on the properties of the material. While studying try to asses the effect of the presence of such group on crystallinity, melting point etc. and consequently tensile strength, flexibility and moisture regain etc. of the fibres.

Polyethylene

Polyester: Including PET and others

Polyamides: Different types of Nylons

Polyaramids: Kevlar and Nomex

While reading up on synthetics there is no need to stress on the synthesis and raw material. All this should be known from TEXT-176. For this course try and focus on the effect of molecular structure and morphology on the properties of the fibres made from a particular synthetic polymers.  

For technical textiles, to be prepared for the exam, presence in class with your brains would have been helpful. To be able to answer the questions in the exam it will be very important to take brains with you, read the questions very carefully, asses what has been asked for and answer with specific information. I will discuss the recent quiz we did in class where the students were to present a case study on one technical textile product area in the last lecture for this course to help students understand how to approach such questions.

The links to the videos that I showed in class from you tube will not be posted here and it is the students’ responsibility to search for appropriate ones and go through them before taking the exam. If you find any interesting material which you feel should be shared with the rest of the class I’d like it if links could be posted as comments. Rest assured there is a chunk of marks allotted to technical textile related case studies in the final exam to be able to solve which one should be well aware of the underlying principles behind technological advancements as discussed in the models that were presented in class including the discussion on the use of hollow fibres to create artificial lungs and the recent case study quiz.

If there’s anything missing here, please post comments.

Second class test model answers

We’ve done quite a bit over this, starting from a lab visit where we observed cotton fibres through the optical microscope through a discussion in class on the morphology of cotton to the handout compiled by MA Wilding from the University of Manchester. All this will be part of the upcoming class test.

You will have to read pages 38 – 49 from Physical Properties of Textile Fibres which provide some good details on the morphology of cotton as well as regenerated celluloses. However, more detail is available in the handout by Wilding.

Below is a list of available downloads on these topics including the slides I taught from. The images in my slides were taken from the Handbook of Fiber Chemistry by Eli M Pearce, a copy of which is available in the library. Those of you who are interested in learning more about cotton and other fibres can also refer to this book.

Lecture 6, properties of major fibre classes

Lecture 7, properties of major fibre classes

Lecture 8, mechanical properties of fibres

Lecture 9, properties of major fibre classes

We’ve already seen in class stress strain curves, and scrutinized them as never done before leaving several mouths agape, some in awe while others yawning, this post will help clarify concepts further.

During the course we realized that we need to spend more time understanding the mechanical properties of textile fibres. These properties were studied using a variety of methods. We started off with an introduction to terms such as strength, elongation and toughness.

A very good introduction to mechanical properties is available on the PSLC. This should be first read to understand basic concepts of mechanical properties such as what tensile strength is, what other types of strengths a fibre can have, what the term toughness corresponds with and what does it mean if a fibre is labelled as tough. These properties have been studied in greater detail from other sources through a facilitated learning quiz where the students were encouraged to look into key issues related to previous concepts. In these notes I will be referring to specific pages from chapter five in PP Saville’s book Physical Testing of Textiles.

Once you’ve gone through the PSLC you should start reading PSCL from page 115 onwards. A separate section is dedicated to each of the properties we discussed in class namely section 5.2 and 5.3.

Breaking strength, tensile strength

Stress

Specific (mass) stress

Tenacity

Breaking length

Elongation

Strain

Extension percentage

Guage length

Yield point

Modulus

Work of rupture

Time dependence

Elastic recovery

These points are discussed in appropriate depth for this course. The sections on different ways to measure moduli and yield point from pages 119 – 126 are meant to help you understand the complexities that may arise in taking such measurements .

Section 5.5 on fibre strength and 5.10 should also be read to further concepts on tenacity,  tensile strength and stretching properties of textile fibres. The rest of the chapter, section 5.4, 5.6, 5.7, 5.8, 5.9 and 5.11, are part of the recommended reading for this course.