Topic: Artificial and synthetic fibres

Target group

High school / technical school student

Core curriculum:

New core curriculum:

High school and technical high school. Chemistry – basic level:

XXI. Chemistry around us. Pupil:

1) classifies fibers into: cellulose, protein, artificial and synthetic; indicates their uses; describes the pros and cons; justifies the need for these fibers;
2) designs and conducts an experiment to identify cellulose, protein, artificial and synthetic fibers.

High school and technical high school. Chemistry – extended level:

XXI. Chemistry around us. Pupil:

1) classifies fibers into: cellulose, protein, artificial and synthetic; indicates their uses; describes the pros and cons; justifies the need for these fibers;
2) designs and conducts an experiment to identify cellulose, protein, artificial and synthetic fibers.

Old core curriculum:

High school and technical high school. Chemistry – basic level:

XXI. Chemistry around us. Student:

1) classifies fibres into: cellulose, protein, artificial and synthetic; indicates their applications; describes the advantages and disadvantages; justifies the necessity of their application;
2) designs and conducts experiments to identify cellulose, protein, artificial and synthetic fibres.

General aim of education

The student discusses and identifies artificial and synthetic fibers.

Key competences

• communication in the mother tongue;

• communication in foreign languages;

• mathematical competence and basic competences in science and technology;

• digital competence;

• learning to learn.

Criteria for success
The student will learn:

• having the fiber concerned, to classify it;

• to indicate and discuss the use of artificial and synthetic fibers;

• to design experience to identify artificial and synthetic fibers.

Methods/techniques

• expository

  • talk.

• activating

  • discussion.

• exposing

  • film.

• programmed

  • with computer;

  • with e‑textbook.

• practical

  • exercices concerned;

  • experiment.

Forms of work

• individual activity;

• activity in pairs;

• activity in groups;

• collective activity.

Teaching aids

• e‑textbook;

• interactive whiteboard, tablets/computers;

• sheets of gray paper;

• colored markers.

Lesson plan overview

Introduction

1. The teacher hands out Methodology Guide or green, yellow and red sheets of paper to the students to be used during the work based on a traffic light technique. He presents the aims of the lesson in the student's language on a multimedia presentation and discusses the criteria of success (aims of the lesson and success criteria can be send to students via e‑mail or posted on Facebook, so that students will be able to manage their portfolio).

2. The teacher together with the students determines the topic – based on the previously presented lesson aims – and then writes it on the interactive whiteboard/blackboard. Students write the topic in the notebook.

Realization

1. The teacher uses the text of the abstract for individual work or in pairs, according to the following steps: 1) a sketchy review of the text, 2) asking questions, 3) accurate reading, 4) a summary of individual parts of the text, 5) repeating the content or reading the entire text.

2. The teacher divides the class into three task groups (there can be a total of six groups). He distributes sheets of paper and colored markers. Each group deals with the development of the issue of one type of fiber, taking into account its advantages and disadvantages as well as the use of: (group I - synthetic fibers, group II - synthetic fibers group III - inorganic fibers). After the work, the group leaders present the effects of the group's work. The teacher summarizes the students' work.

3. The teacher announces a movie titled „Distinguishing between natural and artificial silk”. He instructs his students to write a research question and a hypothesis in the form provided in the abstract. Then he plays the video and the students note their observations and conclusions. The teacher encourages young people to discuss, referring to their inferences.

4. The teacher recalls the participants of the classes to the abstract and asks for familiarization with the experiment's instructions ( „Experiment 2: How to recognize (test) whether the fabric is made of natural or artificial silk (another method)?”). He divides students into groups and distributes the appropriate equipment and materials for performing the experiment. Students follow the instructions. They write observations and conclusions in the form. The teacher indicates the person who presents the results of their work.

5. Students perform an interactive exercise. The teacher discusses the right solution with them.

Summary

1. The teacher briefly presents the most important issues discussed in class. He answers the additional questions of the proteges and explains all their doubts.

Homework

1. Carry out task number 3.

The following terms and recordings will be used during this lesson

Terms

Texts and recordings

Artificial and synthetic fibres

Artificial fibres are fibres produced from natural raw materials – natural polymers, i.e. cellulose, protein, caoutchouc, which are chemically treated.

Viscose is a fibre consisting mainly of cellulose, which is obtained mainly from wood. Viscose fabrics have properties similar to cotton and feel like silk in touch. This is a thermoregulatory and breathable material, absorbing moisture, soft, elastic and pleasant to touch.

Modal is a fibre consisting in 100% of cellulose. The modal production process is very similar to the viscose production process. It is characterized by high resistance to damage and satin gloss. Absorbs 50% more moisture than cotton. Fabrics made of it are airy, soft and elastic. Underwear, sportswear and beddings are made of modal.

Unique bamboo?

There are products on the market whose uniqueness is due to the fact that bamboo fibres were used for their production. The producers and sellers advertising them name a long list of their advantages, which result from the type of fibre used. Do bamboo fibres really have special properties? Well, in terms of chemical composition, these fibres are simply artificial cellulose fibres, for the production of which bamboo was used as a raw material supplying cellulose. Bamboo fibres are made of cellulose obtained from bamboo shoots. Cellulose from trees (spruce, pine, beech) is produced in a similar way and is used for the production of viscose yarn.

Mineral wool (rockwool) is an insulating material of mineral origin. It found application in construction – for thermal and acoustic insulation of walls, ceilings, floors and roofs – and as a raw material for the production of construction materials. For the production of mineral wool, among others, basalt stone and limestone aggregate are used. Recycled materials are also used.

The difference between artificial and synthetic fibres is based on different production technologies. Synthetic fibres are produced by man from the beginning to the end – from synthetic polymers, in the polymerization process (mainly from petroleum and coal), and artificial fibres are created using chemical treatment of natural fibres.

Polyamide (nylon) is the first synthetic fibre. Due to its properties, it gained great popularity among clothing manufacturers. It is lightweight, resistant to crease, very durable, easy to wash and it dries quickly. It is also used as an additive in the form of microfibers (microfiber), e.g. in underwear.

Many types of nylon are produced. The most well‑known is nylon 66 described here. It is formed as a result of the condensation reaction of adipic acid with hexane‑1,6‑diamine. This reaction consists of combining alternating dicarboxylic acid molecules with diamine molecules and forming polymer molecules. Nylon fibre can be obtained by dissolving substrates in water and hexane where substrates form layers instead of mixing together. The polymer forms on the border of these layers. It can be obtained in the form of a long strand.

Polyesters (Terylene, torlen) are synthetic fibres produced in the reaction of dicarboxylic acids with polyhydric alcohols.
These have high resistance to bending, tearing and abrasion, good resistance to light, chemical agents (weak acids and bases), are biologically resistant, absorb water very poorly. Polyester fibres – alone or as a blend with wool, cotton (terylene cotton) or viscose fibres – are used to make fabrics for outerwear, decorative fabrics, curtains.

Elastane (spandex, Lycra) is a polyurethane fibre that was invented in 1958 and immediately revolutionized the clothing industry. The use of elastane as an additive to the materials significantly reduced their weight, while increasing durability as well as comfort and ease of use. Elastane does not appear in the material alone, but as an addition – in blends with other fibres (e.g. with cotton, silk). This fibre is characterized by very high extensibility (up to 500%) and elasticity.

Fleece is a kind of knitted fabric made of PET and other plastics. It is characterized by hydrophobicity and much better thermal insulation properties than wool. It does not lose these properties even if it gets wet. It is used, among others, for the manufacture of sportswear. Currently, various types of fleece fabrics are produced. Depending on the application, these differ in weight (e.g. fleece 100 means that 1 square meter of material weighs 100 grams) and thermal properties, softness and elasticity.

Kevlar is a durable, light and resistant to high temperatures fibre. It is used, among others, for the production of bulletproof vests, helmets, equipment for extreme sports.

Carbon fibres – formed in the process of transforming organic polymers with very long chains contributing to a significant increase in the carbon content in the product. Its important feature is low mass, due to which this material is used in cosmonautics and Formula 1. Currently, due to a significant reduction in production costs, it is also used for the production of many commonly used products.

Among the inorganic fibres, chemical (artificial) fibres are distinguished, including glass and metal fibres.

Glass fibres are made of glass in the form of glass wool used as a material for thermal insulation in construction and in the form of fibres for the production of yarn for clothing fabrics for steelworks workers, filter cloths, theatre curtains. Glass fibres are characterized by high tensile strength, resistance to acids and lixivium, temperature resistance up to 600°C.

Metal fibres are obtained from copper, silver, gold, steel or alloys of these metals. Metal threads are obtained by wrapping cotton or silk yarn with metal wires. These threads are used for embroidery, the manufacture of decorative fabrics. Metal fibre products due to oxidation darken in the air – these should be protected from light and moisture.

• Natural fibres can be cellulose fibres (vegetable fibres) or protein fibres (animal fibres). Mineral fibres (asbestos) are also known.

• Man‑made fibres are chemically synthesized – made of raw materials of natural origin, e.g. viscose from cellulose – and artificial fibres – made of substances obtained by chemical synthesis.

• Today, many types of fibres are produced, which are used to manufacture products that meet sometimes very specialized requirements and serve the safety and comfort of users.

• Observation of fibres combustion allows approximate determination of the type of fibre. In addition, protein fibres undergo reactions characteristic for proteins, e.g. xanthoproteic reaction.