The document discusses polymers and their uses in everyday life. It provides information on different types of polymers like polyethylene, polypropylene, polystyrene, poly(methyl methacrylate), poly(vinyl chloride) and discusses their structures, properties and applications. The document also discusses the synthesis and uses of important polymers.
LDPE is formed from ethylene at a high pressure of 1500-3000 atmosphere at a temperature range of175-250oC in presence of some oxygen, peroxide, or azocompounds as initiators.
LDPE has nearly 20–50 branches (both long and short branches) per 1000 linear carbon atoms in the chain molecules.
The loss of molecular symmetry due to the high degree of branching results in a lower density range (0.915–0.94 g/cm3 ) and lower softening or melting temperature.
LDPE dissolves in toluene at or above 60°C.HDPE is usually more resistant to chemicals than LDPE.
HDPE is soluble in toluene at 900C.
2–5 short branches or side chains per 1000 carbon atoms in the main chain, thus having a higher density range (0.945–0.96) and high melting temperature (125–130°C) compared to LDPE. HDPE-The polymerization at a low temperature and pressure in presence of metal oxide catalyst
Poly ethylenes are very good insulating materials and are adequately flexible hence used as an insulator in wires and cables.
They find extensive uses and applications as molded or formed objects, films, sheets, bottles and containers, pipes, and tubes.
Polythene finds application in packaging, waterproofing, irrigation, and water management including canal lining and mulching, and in coating and lamination.
Polypropylene - Addition polymer
Thermoplastic
Monomer propylene
USES
For making household appliances
In package industry
For making plastic parts of machinery
For making plastic furniture
For making syringes, medical vials, Petri dishes, pill containers, specimen bottles. Polystyrene is synthesized by the polymerization of styrene at 335K in the presence of a benzoyl peroxide initiator. It is used as an electrical insulator.
Expanded polystyrene finds extensive use in packaging and shock absorbing applications, in thermal insulation, and as acoustic improvers in halls and auditoria.
High impact grades are suitable for use as toys, games and sports articles, casings and cabinets for electrical/ electronic gadgets and equipment, and inner liners of refrigerators.
Another major use of polystyrene is in the making of ion-exchange resins. Kevlar is an aromatic polyamide
Five times more tensile strength than steel.
POLYVINYL PYROLIDONE(PVP)(POVIDONE),ETHYLENE VINYL ACETATE (EVA), SARAN , TEFLON (polytetrafluoroethylene) – A fluoro polymer, POLYACRYLONITRILE (PAN),Poly(Methyl Methacrylate) (PMMA), Poly(Hexamethylene Adipamide): Nylon 66, Nylon 6, KEVLAR, Terylene, GLYPTAL, Lexan, POLYURETHANES, UF( Urea –Formaldehyde)
MF (Melamine- formaldehyde)
PF (Phenol-Formaldehyde),MELAMINE FORMALDEHYDE RESIN(MELMAC)(MF), NATURAL RUBBER, VULCANISATION, SYNTHETIC RUBBER, Butadiene rubber(BR), polybutadiene, Buna-S, BUNA- N, EPDM ( ethylene, propylene, diene monomer) , Neoprene, silicone rubber, Pollution due to plastics , and recycling of plastics are the other topics discussed here.
LDPE is formed from ethylene at a high pressure of 1500-3000 atmosphere at a temperature range of175-250oC in presence of some oxygen, peroxide, or azocompounds as initiators.
LDPE has nearly 20–50 branches (both long and short branches) per 1000 linear carbon atoms in the chain molecules.
The loss of molecular symmetry due to the high degree of branching results in a lower density range (0.915–0.94 g/cm3 ) and lower softening or melting temperature.
LDPE dissolves in toluene at or above 60°C.HDPE is usually more resistant to chemicals than LDPE.
HDPE is soluble in toluene at 900C.
2–5 short branches or side chains per 1000 carbon atoms in the main chain, thus having a higher density range (0.945–0.96) and high melting temperature (125–130°C) compared to LDPE. HDPE-The polymerization at a low temperature and pressure in presence of metal oxide catalyst
Poly ethylenes are very good insulating materials and are adequately flexible hence used as an insulator in wires and cables.
They find extensive uses and applications as molded or formed objects, films, sheets, bottles and containers, pipes, and tubes.
Polythene finds application in packaging, waterproofing, irrigation, and water management including canal lining and mulching, and in coating and lamination.
Polypropylene - Addition polymer
Thermoplastic
Monomer propylene
USES
For making household appliances
In package industry
For making plastic parts of machinery
For making plastic furniture
For making syringes, medical vials, Petri dishes, pill containers, specimen bottles. Polystyrene is synthesized by the polymerization of styrene at 335K in the presence of a benzoyl peroxide initiator. It is used as an electrical insulator.
Expanded polystyrene finds extensive use in packaging and shock absorbing applications, in thermal insulation, and as acoustic improvers in halls and auditoria.
High impact grades are suitable for use as toys, games and sports articles, casings and cabinets for electrical/ electronic gadgets and equipment, and inner liners of refrigerators.
Another major use of polystyrene is in the making of ion-exchange resins. Kevlar is an aromatic polyamide
Five times more tensile strength than steel.
POLYVINYL PYROLIDONE(PVP)(POVIDONE),ETHYLENE VINYL ACETATE (EVA), SARAN , TEFLON (polytetrafluoroethylene) – A fluoro polymer, POLYACRYLONITRILE (PAN),Poly(Methyl Methacrylate) (PMMA), Poly(Hexamethylene Adipamide): Nylon 66, Nylon 6, KEVLAR, Terylene, GLYPTAL, Lexan, POLYURETHANES, UF( Urea –Formaldehyde)
MF (Melamine- formaldehyde)
PF (Phenol-Formaldehyde),MELAMINE FORMALDEHYDE RESIN(MELMAC)(MF), NATURAL RUBBER, VULCANISATION, SYNTHETIC RUBBER, Butadiene rubber(BR), polybutadiene, Buna-S, BUNA- N, EPDM ( ethylene, propylene, diene monomer) , Neoprene, silicone rubber, Pollution due to plastics , and recycling of plastics are the other topics discussed here.
poly styrene is a synthetic aromatic polymer made from the monomer styrene. Polystyrene can be solid or foamed. General purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight. polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled .
Melamine resin or melamine formaldehyde is a hard, thermosetting plastic material made from melamine and formaldehyde by polymerization. The presentation includes the preparation of MF, its properties and applications.
poly styrene is a synthetic aromatic polymer made from the monomer styrene. Polystyrene can be solid or foamed. General purpose polystyrene is clear, hard, and rather brittle. It is an inexpensive resin per unit weight. polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 °C, its glass transition temperature. It becomes rigid again when cooled .
Melamine resin or melamine formaldehyde is a hard, thermosetting plastic material made from melamine and formaldehyde by polymerization. The presentation includes the preparation of MF, its properties and applications.
This presentation is all about plastics and its types. It includes polythene,polyesters,polystyrene,and other forms of plastics.Various examples are also shown for proper explanation.
To analyze the influence of tire properties on the dynamic behavior of vehicles, the engineer requires an accurate description of the tire-road contact phenomena
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Industrial Training at Shahjalal Fertilizer Company Limited (SFCL)MdTanvirMahtab2
This presentation is about the working procedure of Shahjalal Fertilizer Company Limited (SFCL). A Govt. owned Company of Bangladesh Chemical Industries Corporation under Ministry of Industries.
Online aptitude test management system project report.pdfKamal Acharya
The purpose of on-line aptitude test system is to take online test in an efficient manner and no time wasting for checking the paper. The main objective of on-line aptitude test system is to efficiently evaluate the candidate thoroughly through a fully automated system that not only saves lot of time but also gives fast results. For students they give papers according to their convenience and time and there is no need of using extra thing like paper, pen etc. This can be used in educational institutions as well as in corporate world. Can be used anywhere any time as it is a web based application (user Location doesn’t matter). No restriction that examiner has to be present when the candidate takes the test.
Every time when lecturers/professors need to conduct examinations they have to sit down think about the questions and then create a whole new set of questions for each and every exam. In some cases the professor may want to give an open book online exam that is the student can take the exam any time anywhere, but the student might have to answer the questions in a limited time period. The professor may want to change the sequence of questions for every student. The problem that a student has is whenever a date for the exam is declared the student has to take it and there is no way he can take it at some other time. This project will create an interface for the examiner to create and store questions in a repository. It will also create an interface for the student to take examinations at his convenience and the questions and/or exams may be timed. Thereby creating an application which can be used by examiners and examinee’s simultaneously.
Examination System is very useful for Teachers/Professors. As in the teaching profession, you are responsible for writing question papers. In the conventional method, you write the question paper on paper, keep question papers separate from answers and all this information you have to keep in a locker to avoid unauthorized access. Using the Examination System you can create a question paper and everything will be written to a single exam file in encrypted format. You can set the General and Administrator password to avoid unauthorized access to your question paper. Every time you start the examination, the program shuffles all the questions and selects them randomly from the database, which reduces the chances of memorizing the questions.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
2. Now-a-days polymers are being used in many
fields viz. fabrics, plastic bottles, switch boards &
many more to come. Polymers find their extensive
use because of the ease in working with them.
They can also be reused & some of them can even
be recycled which has also cut down the damage
which was earlier being caused by the non-
biodegradable substances.
In our project we are going to introduce you with
some of the polymers being used daily, their
structures & synthesis.
3. Exist in countless forms.
Chemical structure.
Physical properties.
Mechanical behaviour.
Thermal characteristics.
4. Which are isolated from natural material are called
natural polymers.
COTTON
SILK
WOOL
RUBBER
Which are synthesized from low molecular weight
compound are called synthesized polymers.
POLYETHYLENE,PVC,NYLON &TERYLENE
5. Whose backbone chain is made of carbon atoms is
termed as organic polymer.
POLYPROPYLENE
PVA
PMMA
Which contain no carbon atom in their backbone
chain are called inorganic polymers.
GLASS
SILICON RUBBER
6. Which can be soften on heating and can be converted
into any shape that they can retain on cooling.
POLYETHYLENE
PVC
NYLON
SEALING WAX
Some polymers undergo some chemical changes on
heating and convert themselves into an infusible
mass are called thermosetting polymers.
PHENOL FORMALDEHIDE
POLYESTERS
7. When a polymer is shaped into a hard and tough
utility article ,it is used as plastics.
POLYSTYRENE
PVC
PMMA
When polymer vulcanized into a rubbery products
exhibiting good strength and elongation ,it is used
as elastomers.
NATURAL RUBBER
SYNTHETIC RUBBER
SILICONE RUBBER
8. If it is drawn into long filament like materials ,it is
used as fibers.
NYLON
TERYLENE
Polymer used as adhesive ,potting compounds
,sealants ,etc., in a liquid form are described as
liquid resins.
POLYSULPHIDE
MELAMINE FORMALDEHIDE
9.
10. It is the simplest hydrocarbon polymer and has the
structure-:
It was first introduced by Imperical Chemical
Industries(ICI) in 1993.
It is a thermoplastic polymer.
There are two varieties of polyethylene viz., high
density polyethylene and low density polyethylene.
11. Has low degree of branching & thus low
intermolecular forces.
Density- greater or equal to 0.941g/cm3.
Crystalinity is 90%.
Melting point is in the range from 144-150 degree
Celsius.
Higher tensile strength and hardness than LDPE.
12. Has a high degree of short and long chain
branching.
Density range-: 0.910-0.940.
Crystalinity is 40%.
Melting point range-: 110-125 degree Celsius.
13. LDPE films are mainly used for packaging and
wrapping frozen food.
LDPE’s inertness to chemicals and resistance to
breakage is made use of it in ‘squeeze bottles’ and
in many attractive containers.
Also used as insulation in electric cables.
HDPE finds better use in the manufacture of toys
and other household articles.
Whenever high tensile strength and stiffness are
required, HDPE finds better use.
14. Propylene was first polymerized to a crystalline
isotactic polymer by Guilio Natta as well as by the
German chemist Karl Rehn in March 1954.
Polypropylene is a Highest industrial plastic.
15. THE POLYPROPYLENE is formed by Polymerization
of propylene using zigelar-natta catalyst .
Propylene is obtained from gasoline refineries as
a byproduct.
16. It can be made in three form, isotactic, syndiotactic
and atactic.
Isotactic polypropylene ,it is a highly crystalline
polymer with melting point 165°C.
It has a very high tensile strenght, hardness,
stiffness.
It is insoluble in many solvent.
It’s melting point is 130–171 °C .
It’s density for amorphous & crystalline is0.855
g/cm3 & 0.946 g/cm3 respectively.
17. Polypropylene (PP), is a thermoplastic polymer used
in a wide variety of applications including
packaging and labeling , textiles (e.g., ropes,
thermal underwear and carpets), stationery, plastic
parts and reusable containers of various types,
laboratory equipment, loudspeakers, automotive
components, and polymer banknotes.
19. Polystyrene results when styrene monomer
interconnect
Carbon- Carbon pi bond is opened up and new
sigma bond is formed
20. Various Applications of
Polystyrene
•Manufacturing
•Disposable cutlery
•Household appliances
like blenders, air
conditioners ,ovens
•Other consumer goods
like kitchen and
bathroom accessories
•Housing for televisions
and CD & DVD cases
•Owning to its less price
as compared to other
costly polymers thus
also used for making
toys
21. •Packaging
•Supermarket are stocked up with eatables stored in
polystyrene packaging materials . Meat , fish , eggs,
dairy products, salad etc. can be prevented from
spoiling.
•Electronic goods and appliance are packed in boxes
along with support materials made up of polystyrene
that provides insulation and protect from external
factors
22. • Used for construction purposes to insulate ceiling
,walls , floor etc.
• This polymer also find its utility in sound
proofing walls of buildings
• Lightning and plumbing fixtures , panel and
sidings used for construction purposes
23. •Medical applications
•Versatility of this resin has
made it suitable for use in the
medical field as well
•Extensively used in the
making of medical equipment
due to clarity and fitness
•Test tubes , Petri dishes ,
trays for conducting tissues
culture test etc.
•Many diagnostic equipment
are also made up of
polystyrene . Medical cups ,
medical keyboards , plastic
boxes are some examples of
the same
24. •Art and craft
•XPS can be used for art
and craft works
•Candle holders and
ornament for a Christmas
tree can be accomplished
by Styrofoam
•Making models of
architectural design
25. Poly(methyl methacrylate) (PMMA) is a transparent
thermoplastic, ofTen used as a lightweight or
shatter-resistant alternative to glass.
26. The first acrylic acid was created in 1843.
Methacrylic acid, derived from acrylic acid, was
formulated in 1865.
The reaction between methacrylic acid and
methanol results in the ester methyl methacrylate.
The German chemists Wilhelm Rudolph Fitting and
Paul discovered in 1877 the polymerization process
that turns methyl methacrylate into polymethyl
methacrylate
27. PMMA is routinely produced by emulsion
polymerization, solution polymerization, and bulk
polymerization. Generally, radical initiation is used
(including living polymerization methods), but
anionic polymerization of PMMA can also be
performed.
To produce 1 kg (2.2 lb) of PMMA, about 2 kg
(4.4 lb) of petroleum is needed.
PMMA produced by radical polymerization(all
commercial PMMA) is atactic and completely
amorphous.
28. PMMA is a strong and lightweight material. It has a
density of 1.17–1.20 g/cm3,, which is less than
half that of glass.]
It also has good impact strength, higher than both
glass and polystyrene;
however, PMMA's impact strength is still
significantly lower than polycarbonate and some
engineered polymers.
PMMA ignites at 460 °C (860 °F) and burns, forming
carbon dioxide, water, carbon monoxide and low-
molecular-weight compounds, including
formaldehyde.
30. ● Poly(vinyl chloride), commonly abbreviated as PVC,
is the third-most widely produced plastic, after
polyethylene and polypropylene.
● Pure PVC is a white, brittle solid. It is insoluble in
alcohol but slightly soluble in THF.
31. ● PVC was discovered accidently at least twice in the
19th century, first in 200 by French chemist Henri
Victor Regnault and then in 1872 by German
chemist Eugen Baumann.
● On both occasion the polymer appeared as a white
solid inside flasks of vinyl chloride that had been
left exposed to sunlight.
● In the early 20th century the Russian chemist Ivan
Ostromislensky and Fritz Klatte of the German
chemical company Griesheim-Elektron both
attempted to use PVC in commercial products, but
difficulties came due to rigidness.
32. Waldo Semon and the B.F Goodrich Comany
developed a method in 1926 to plasticize PVC by
blending it with various additives. The result was a
more flexible and more easily processed material
that soon achieved widespread commercial use.
33. ● Poly(vinyl chloride) is produced by polymerization
of the monomer vinyl chloride (VCM), as shown.
● About 80% of production involves suspension
polymerization.
34. ● Weathering stability- PVC is resistant to aggressive
environmental factor is therefore the material of choice for
roofing.
● Versatility- PVC can be flexible or rigid.
● Fire protection- PVC is a material resistant to ignition due to
its chlorine content.
● Longevity- PVC products can be last up to 100 yrs. and even
more.
● Hygiene- PVC is a material of choice for medical applications,
particularly blood and plasma storage containers.
● Eco efficiency- Only 43% of PVC'S content comes from oil
(57% comes from salt); it therefore contributes to the
preservation of that highly valuable resource.
● Economical efficiency- PVC is the cheapest of large-tonnage
35. ● There are 2 types of PVC'S.
● Rigid PVC- it exhibits high surface strength and very good
rigidity. It is used mainly for pipes, windows.
● Plasticized PVC- added with plasticizers which gives it
flexibility which is used in the manufacture of films,
expanded products, sheets, jacketing for electrical cables
etc.
● In building and construction- PVC windows and doors,
frames, shutters, panels, piping for drinking water
distribution, flooring etc.
● In packaging- In foodstuffs and pharmaceuticals.
● In cars- panels for car doors, dashboards, electrical cabinets,
matting.
● In electricity and electronics- jacketing of electrical cables for
36.
37. The high thermal stability of the carbon fluorine
bond has led to considerable interest in fluorine
containing polymers as a heat resistant plastics
and rubbers.
38. The first patent taken out by i.g farben in 1934
related to poly chloro tri flouro ethylene. PCTFE has
been of limited application and it was the
discovery of poly tetra flouroethylene by Plunkett in
1938
39. TEFLON WAS FIRST PREPARED IN 1933.
THE CURRENT COMMERCIAL SYNTHESIS OF TEFLON
ARE BASED ON SULPHURIC ACID , FLOUROSPAR
AND CHLOROFORM.
40. PTFE IS MADE COMMERCIALY BY TWO METHODS.
GRANUEL METHOD
DISPERSION OF POLYMER OF MUCH FINER PARTICLE
SIZE AND LOWE MOLECULAR WEIGHT.
41. THE PROPERTIES OF PTFE ARE DEPEND ON THE
TYPE OF POLYNMER AND THE METHOD
PROCESSING
IT IS OBSERVED THAT THE DISPERSION POLYMER
WHICH OF FINE PARTICLE SIZE AND LOWER
MOLECULAR WEIGHT , GIVES PRODUCTS WITH A
VASTLY IMPROVED RESISTANCE TO FLEXING AND
DISTINCTLY HIGHER TENSILE STERNGTH.
42. CHEMICAL INERTNESS
EXECPTIONAL WHETHER RESISTANCE
THE EXCELLENT HEAT RESISTANCE
NON ADHESIVE PROPERTIES
VERY LOW VALUE OF CO-EFFICIENT OF FRICTION.
43.
44. Formaldehyde is an organic compound with the
formula CH2O or HCHO. It is the simplest
aldehyde, hence its systematic name methanal. The
common name of the substance comes from its
similarity and relation to formic
acid. formaldehyde is colourless and has a
characteristic pungent, irritating odour.
45. Formaldehyde is produced industrially by the
catalytic oxidation of methanol.It is also known as
formox process.
In this reaction methanol and oxygen react in
presence of iron oxides at a temperature of 250–
400 °C
2 CH3OH + O2 → 2 CH2O + 2 H2O
Dehydrogenation method
CH3OH → H2CO + H2
46. Formaldehyde is also a precursor to polyfunctional
alcohols such as pentaerythritol [ C5H12O4 ], which
is used to make paints and explosives.
The textile industry uses formaldehyde-based
resins as finishers to make fabrics crease-resistant.
When treated with phenol, urea, or melamine,
formaldehyde produces, respectively, hard
thermoset phenol formaldehyde resin, urea
formaldehyde resin, and melamine resin. These
polymers are common permanent adhesives used
in plywood and carpeting.
47. An aqueous solution of formaldehyde can be useful
as a disinfectant as it kills most bacteria and fungi.
formaldehyde solutions are commonly used as a
biological preserving medium.
Formaldehyde, along with 18 M (concentrated)
sulphuric acid makes Marquis reagent which can be
used to identify alkaloids and other compounds.
48. • Most Of these are non biodegradable which can harm
our environment and thus can lead to imbalance in the
nature.
• When polymer incorporated with additives and when
they are burnt, they emit a lot of poisonous gases into
the atmosphere which results in choking.
• Low molecular weight polymers are difficult to recycle.
• Undergo oxidation and ozonation easily which can
result in the increase of ozone hole size.
49. As you have seen that polymer is not a single
compound. It has a large variety. All the different forms
of polymers comes under one umbrella. From a simple
Polyethylene to a complex composites, all comes under
the heading of polymers.
We have shown you that many polymers are having a lot
of advantages in the spectrum of industrial level. But at
the same time you have also seen the disadvantage of
this polymer.
As the saying says. Every Coin Has Two Sides.