• Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month
Page
  1. 1
    1
  2. 2
    2
  3. 3
    3
  4. 4
    4
  5. 5
    5
  6. 6
    6
  7. 7
    7
  8. 8
    8
  9. 9
    9
  10. 10
    10
  11. 11
    11
  12. 12
    12
  13. 13
    13
  14. 14
    14
  15. 15
    15
  16. 16
    16
  17. 17
    17
  18. 18
    18
  19. 19
    19
  20. 20
    20
  21. 21
    21
  22. 22
    22
  23. 23
    23
  24. 24
    24
  25. 25
    25
  26. 26
    26
  27. 27
    27
  28. 28
    28
  29. 29
    29
  30. 30
    30
  31. 31
    31
  32. 32
    32
  33. 33
    33
  34. 34
    34
  35. 35
    35
  36. 36
    36
  37. 37
    37
  38. 38
    38
  39. 39
    39
  40. 40
    40
  41. 41
    41
  42. 42
    42
  43. 43
    43

EFFECT OF MOISTURE ON THE MECHANICAL PROPERTIES OF NYLON

Extracts from this document...

Introduction

EFFECT OF MOISTURE ON THE MECHANICAL PROPERTIES OF NYLON REPORT BY FAIZAN ANWER HOZEFA NAJEEB PROJECT ADVISOR YASSER JAFFER PREFACE Nylon emerged as commercial thermoplastics after the Second World War following their remarkable wartime success in the textile field. The large scale production of Nylon plastics grew mainly from the adoption of conversion methods and equipment already used for other thermoplastics, together with the availability of relative cheep raw material for bulk manufacture of the polymers. In this report an attempt has been made to present, a broad but balance picture of present day Nylon plastics technology. The topics follow the sequence adapted for monographs on plastic materials in this report and cover raw materials, polymerization techniques, and properties with an historical introduction and testing. While the emphasis is largely based on the effect of moisture on Nylon 6. In discussing properties necessitate is emphasized to obtain the reliable design data to exploit the unique combination of properties possessed by Nylon. In compiling this report a large number of references were consulted, and those from which data were selected for inclusion are listed at the end of the report. SUBJECT Moisture as a matter of fact affects the polymer in respect to their properties and other areas as well, as water molecules may enter the structure of polymer (hygroscopic materials) or may only settle on their surface (hydroscopic materials). In case of hygroscopic materials, as Nylon is, it is very significant to remove the water content from its molecules as they form a primary bond within the polymeric material and hence changes the performance and properties which were expected previously from the polymer. This state of affair raises problems in processing and design of component made from polyamides, for not only most important properties considerably are affected by the water absorption but also the dimensional changes may occur that can affect the functioning of components. ...read more.

Middle

This is done by blowing air heated to a temperature of 550*F through the desiccant beds. The elevated temperature drives the moisture out of the beads and into the ambient air. A multiple desiccant bed absorption system is the most efficient method for drying. A common absorption bed setup is double bed system. In double bed system, one bed is online drying material, while the other bed is in regeneration cycle. There are two types of air flow direction to regenerate desiccant bed: counter-current and co-current. When the desiccant bed is in working mode, the beads act like a sponge with water poured on one side of it. The water does not get dispersed evenly through the bed. Beads that make contact with the wet air will become moist first. Once these beads reach the saturation point, other beads in close proximity become saturated. This process continues until all the beads are saturated. In counter-current regeneration the air flows through the desiccant bed in the opposite direction of working airflow. This forces the moisture out of the desiccant bed opposite the direction in which it entered. The advantage of this is that the bed can be regenerated faster. Dehumidifying dryers are sized similar to the hot air drying system. The hopper is sized by the production rate multiplied by the residence time. The dryer is then sized by the corresponding figures from the dryer sizing chart. The dryers are sized on a flow rate of 50ft/min. If the flow is more than 50ft/min the material will be blown around in the hopper. Any flow rates considerably less than 50ft/min may not have enough velocity to dry the plastic material. Table: Drying times & air velocities for carrousel-type dryers at 160*F (71*C) Nylon Water Time Air velocity % (hr) 120 ft /min.(.057m /sec) 240 ft /min.(.113m /sec) Hopper capacity Output Hopper capacity Output 11 or 12 1 2 260 lb (118 kg) ...read more.

Conclusion

- The thickness of test sample is too much to carry out izod impact for this particular tough polymer. * Observations made during processing of test samples. - While processing specially dried material, it was observed that resin needed a high injection pressure to fill in the cavity, although melt temperature was checked time and again and a bit was increased when needed. This could have been due to over drying of material, which had moisture content of less than 0.094% (which automatically makes resin more viscous). The other possible reason could be the screw used in the injection-molding machine was a conventional type screw, which might regret such hard and crystalline material in flow case. - Splash marks were observed on the molding of undried resin, which might have been because of the volatiles (water) trapment in the barrel. Since the water content level for undried resin was a higher one (3%). The other possible reason could be air trapment in barrel while the hopper feeding wasn't proper or the hopper cover was putted off for a longer period. - A slight color change (yellowish) was observed on the few of the moldings, although they were discarded due to slight over heating. The reason was the same less flow ability shown, especially by dried material. * Market survey. - A local market survey was carried out which made an impression that Nylon wasn't easily available in market and if they do, there isn't enough range of grades and diversity exists. Few of the grades available and their prices are quoted as under: TRADE NAME RATES * ZYTAL (DuPont plastics) 3500/- * NOVAMID (Mitsubishi Plastics) 3750/- * TORAY (1017) 3550/- * U.B.E (1013) 3400/- * Ultramid B35 (BASF Plastics) 3675/- CONCLUSION Polyamides are very much moisture attractive and this moisture content affects a great deal in reducing the mechanical properties of material. The moisture content in polyamides dealt appropriately before processing, in order to achieve the desired and naturally possessed properties of Nylon. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our GCSE Resistant Materials section.

Found what you're looking for?

  • Start learning 29% faster today
  • 150,000+ documents available
  • Just £6.99 a month

Not the one? Search for your essay title...
  • Join over 1.2 million students every month
  • Accelerate your learning by 29%
  • Unlimited access from just £6.99 per month

See related essaysSee related essays

Related GCSE Resistant Materials essays

  1. Metallography. The objective of our experiment is to learn specimen preparation techniques in metallography ...

    Plastic mounting devices can be subdivided into two categories, thermosetting resins which require heat and pressure to transform into a plastic cast and thermoplastic resins which are castable at room temperature. Thermosetting resins come in a powder form and can be ejected from the mold at molding temperature.

  2. Analysis of Existing Products.

    Wood is cut from tress, and therefore by using wood we are cutting more and more trees. But if these trees are re-grown then the impact on the environment could almost reduce to zero. Then metal is also harmful to the environment.

  1. ORMOCER®s - A new class of polymeric material.

    Glass, for example, can be considered an inorganic network polymer based on silicon-oxygen chains, and its brittleness, high melting temperature and extreme transparency are properties clearly very different from those of typical organic polymers. Just as it is possible to develop useful organic copolymers by the polymerisation of carefully selected

  2. What factors affect the cooling of hot water in a container?

    Cut appropriate size of the insulating material and Sellotape all the way around the sides of the beaker. Cut an extra piece to go over the top but do not situate until step 3. (Placing the material around the sides decreases the amount of radiation, on top, reduces convection, and

  1. Work efficiently and effectively at electrical wiring and testing.

    If the problems do occur then it's the best course of action to report the damage to your supervisor to ensure the safety and well being of the rest of the workforce. * It is important to maintain good housekeeping and equipment control to ensure the safety of the workforce

  2. The Effect of Different Types of Insulation on Heat Retention

    Consequently, it kept water hot for the longest period of time, as the heat absorption occurring was gradual as well. Aluminium is a metal; metals are good conductors of heat and electricity, which means that they transfer energy from one particle to another. This is known as the collision theory.

  1. Explain Aristotle idea of the four causes.

    Of these the last is the most fundamental and important. Secondly there is efficient cause. This cause explains something in terms of its essence or "pattern." A question that is relevant to this cause is, how does it happen? This is the agent or force immediately responsible for bringing this

  2. TENSILE TESTING OF METALS

    Area 20mm2 10mm2 20mm2 20mm2 Composition 0.1% C steel 0.54% C steel Aluminium 4% Copper Alloy Pure Aluminium Condition Normalisation at 900`c Oil Quenched from 840`c and Tempered at 550`c None Heat treated at 505`c, water quenched and naturally aged Observation Black Mat finish, very hard, Black, light weight, small, not very thick Silver, shiny, Thicker than previous 2 samples.

  • Over 160,000 pieces
    of student written work
  • Annotated by
    experienced teachers
  • Ideas and feedback to
    improve your own work