Tec Bil 3º

Dear Students,
Leave here all the comments and suggestions you like. I hope we will have a course full of good things.

Remember: 1) I am at your entire disposal here or email for pupils (see antoniocuestas.com)

2) Check former blogs (see links, enlaces a cursos pasados) if you need more materials for your lessons



Fotos trabajo de plásticos de otros años

Fotos de proyectos de plásticos y teoría (en inglés)
Propiedades de los plásticos
Las principales propiedades de los plásticos son:
> Su plasticidad, o capacidad para deformarse, lo que permite que con ellos se
puedan fabricar piezas mediante la aplicación de calor y el uso de moldes.
> Su facilidad para darles color añadiendo tintes en el proceso de fabricación y su
buen aspecto final sin que sean necesarias operaciones de acabado en la mayoría
de los casos.
> Su ligereza y capacidad aislante de la electricidad y el calor.
> Su resistencia mecánica, que aunque no muy elevada, es suficiente en la mayoría
de sus aplicaciones.
> Su resistencia a la acción de agentes atmosféricos y corrosivos.
Su principal inconveniente es su eliminación o reciclado.
Comenzamos con los plásticos. Su lenguaje es complicado en español así que en inglés más. Pero no os preocupéis veréis cómo con las clases, actividades y proyectos que haremos con ellos los aprendéis. Aprovecho las notas que tomó vuestra compañera Aida, gracias Aida, para ir empezando con el vocabulario. Las notas están tomadas por ella en clase, hay algún pequeño comentario que hacer y las repasaremos y corregiremos en clase pasado mañana. Ciao¡
¡¡Tenéis que poneros las pilas para el examen de los plásticos!! “You have to put the batteries in” (Traducción propia) 🙂

‘polymer==> ‘POLYMERIZATION/ai/

Capacity to change and adapted the shape-capacidad de darles forma
They can be coloured-pueden ser coloreados, (dye-teñir)
They are light-son ligeros
They have a very good insulation(aislante) from electricity and heat-son buenos aislantes de la electricidad y el calor
Good mechanical re’sistance
Very resistent to acids, atmospheric agents, corrosives but at the same time its great inconvenience. Difficult to recycle it.
Accumulation causes serious problems for the environment

There are two big groups:
–Thermoset (termoestables): you can only shape/mould/form once (solo les puedes dar forma una vez)
–Thermoplastic (termoplásticos): you can shape them as often as you like (les puedes dar forma las veces que quieras)


Bakelite -used in the electronic circuits (se usan en circuitos electrónicos), plaques
Melamine Used for covering surfaces
Polyester ‘tergal, terlenka==> don´t crease, they dry very quickly
Mixturing with fibreglass it is very useful for e.g. canoes /ka’nus/
Cellulosic plastic
Cellulose ace’tate /seliolous/ Used for transparencies

Polyethylene bottles, containers, plastic bags. North Sea gas==>pipes
Polyethylene terephthalate \ˌter-ə(f)-ˈtha-ˌleit\(PET), plastic bottles (e.g.mineral water)
PVC, Initial letters don’t confuse with ‘acronyms
Polyvinyl chloride \ˌpä-lē-ˈvī-nəl\//cl’oraid/

used in: containers, fall pipes (rain) or drain pipes (toilet)
windows frames, electric cable covers, boxes for electrical installations

Poly(methyl methacrylate) (PMMA)\ˈpä-lē-ˌme-thəl-\polimezl mezacrileit
It is v. transparent, for optical lenses, signs for companies or for ex. when you go out of this building (main entrance) you can see one(Misioneras Claretianas)
It is resistant so we can use it in aircraft windows-
To protect photos its the best, keyrings.

Polystyrene (pronounced /ˌpɒliˈstaɪriːn/) )
good mechanical resistence, very useful for outdoor furniture, pens,

Expanded polystyrene which is very useful as foam packaging

Polypropylene\ˌpä-lē-ˈprō-pə-ˌlin\ (PP) videocases, syringes, the exterior of a car battery (case),cords, rafia,

Very resistant, forms threads/e/easily. Used for gears, textiles (textails/, (cords,ropes)

Recycling of plastics
. Don´t desintegrate with the passing of time//Don´t degrade or decompose over time
. Accumulation causes serious problems for the environment
. We have to recover other types of material (Al, glass, paper…)
Recycling is collecting and transforming materials that are considered rubbish into useful products

Selective collection makes it easier
The main problem is separating and clening, expensive and complicated
Effectiveness: depends on citizenship collaboration
4 types of recycling
Primary: from waste, we get plastics with the same properties as the original
Secondary: They have less quality as the original
Terciary: break down into chemicals and fuel
2 methods: pyrolysis, without contact with the fire-> gases and smoke ==> very complex processes -> tar, fuel (petrol / gasoline) and raw materials -> Plastics
Gasification= Pyrolysis but more temperature and pressure.
Gas obtained-> produces electricity, methanol or ammonia
Cuaternary:incineration-> heat-> steam generators, for drying furnaces
Disadvantages: Very pollutant and expensive

Plastics manufacturing
Injection: grains melted / Founded, heating, plunger, screw
Extrusion: The process of molding plastics for making profiles or tubing
Blowing: Bottles
Compression: Thermoset
Plastics manufacturing

Injection: grains melted / Founded, heating, plunger, screw

Extrusion: The process of molding plastics for making profiles or tubing

Blowing: Bottles

Compression: Thermosets

How to cut plastics
Expanded polystyrene: heated metal thread
rigid plastics: saw, scratch , breaks off
Sheets of plastic: scissors
Rigid Plastics Drilling: slowly, to prevent breakage and chips jumping// flying chips


5 comentarios en “Tec Bil 3º

  1. Exercises of electricity

    What voltages and intensities of output will be obtained from a transformer with 50 turns in the primary. The input voltage is 20 volts. In the secondary there are 2 coils with 50 and 300 turns. R=5 ohms
    Calculate the power that is used by a heater connected to 220 V if it has a resistance of 60 O.
    Find the intensity which/that circulate in a device which consumes 440w if the voltage it receives is 220v
    In our home we have a computer which is powered at 250 W and a lamp powered at 100 watts.How much will we have to pay the electrical company each month if the computer is used an average of 2h/day and the lamp 4h/day. Price= 0.1€ Kw.h
    What ouput voltages and intensities will be obtained from a transformer with 100 turns in the primary, the input voltage is 20 volts. In the secondary there are 2 coils with 50 and 300 turns respectively? R=5O
    Calculate the power consumed by a heater connected at 220 V if it has a resistance of 30 O
    Calculate the intensity circulating in a device which consumes 200 W if the input voltage is 220 V

    If you want to practice more:

    Me gusta


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