What is PVC and uPVC?

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29 Νοε 2013 (πριν από 3 χρόνια και 6 μήνες)

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What is
PVC and
uPVC?


Plastics are classified into two categories: thermoplastic resins and thermosetting resins. The main difference is
thermosetting resins are thermally hardened and never become soft again (because they
include

phenol

resin and
melamine resin) but thermoplastic resins can be re
-
softened by heating (PVC,PE,PS,PP).


PVC

(Polyvinyl Chloride) is a
chemical

compound of chlorine, carbon and hydrogen

which is produced by
polymerization of t
he monomer vinyl chloride (VCM). It
is a vinyl polymer constructed of repeating vinyl groups
(
ethylenes
) having one hydrogen replaced by chloride.




PVC is made of 43% carbon (derived predominantly from oil/gas via
ethylene
) and 57% chlorine (derived from
industrial gas). PVC is a natural
resource saving plastic

because it is less dependent th
an other polymers on crude oil
or natural gas (which are nonrenewable). On the other hand chlorine gives ex
cellent fire resistance to PVC, it has a
self
-
extinguishing property; when
it’s

on fire, t
he
f
lame goes

out as the fire source is removed
.


Since PVC has polar groups (chlorine), and is amorphous, therefore mixes well with various other substances. The
required physical properties of end products (e.g., flexibility, elasticity, impact resistance, a
nti
-
fouling, prevention of
microbial growth, anti
-
mist, fire retarding) can be freely designed through formulation with plasticisers and various
additives, modifiers, and colouring agents. PVC is the only general purpose plastic that allows free, wide and
seamless adjustment of the required physical properties of products such as flexibility, elasticity, and impact
resistance, by adding plasticisers, additives, and modifiers.
The raw
material without

the
se additives and
stabilizers is
called
uPVC
;

where “u
” stands for plasticizers


unplasticized
, means that the material has not been softened by the
addition of chemicals known as plasticizers.


Physical
and Mechanical
Properties of PCV

(PVC.org dan alıntılar yapılarak, cümleler
tamamen/kısmen
değiştirilmiştir…kaynak
olarak verilmesi faydalı
olacaktır
…kısmen wikipedia
, uni
-
bell

ve pvcpipeassociation

dan da bilgiler bulunmaktadır..
)


T
he features
of general purpose plastics, PVC
-
PE
-
PS
-
PP,
are determined by its chemical composition and type of
mo
lecular structure (crystalline/amorpous).

Among these plastics PVC is the only one that has an
amorphous
structure with polar chlorine at
oms in the molecular structure which
are inseparably related.


I
n the context of daily use

plastics seem very similar but
PVC has completely different features in terms of
performance and functions compared with olefin plastics which have only carbon and hydrogen atoms in their
molecular structures.




Molecular structures of general purpose

plastics


Chemical stability is a common feature among substances containing halogens such as chlorine and fluorine. This
applies to PVC resins, which furthermore possess fire retarding properties, durability, and oil/chemical resistance.


Fire retarding
properties

Due to its chlorine content PVC has inherently superior fire retarding properties, even in the absence of fire
retardandts.
Thanks to its
self
-
extinguishing property,

even w
hen its on fire, the flame go out as the fire source is
removed.


Self ignition temperature of PVC is 455°C and since it’s not ignited easily
it has less risk for fire incidents.
Furthermore, in comparison to PE and PP the heat released in burning is considerably lower with PVC, therefore
contributes much less to spreadi
ng fire to nearby materials even while burning.




There may be many ways of evaluating the fire retarding properties, but the oxygen index can be used for the
evaluation with a comparatively high precision and reproducibility of the results. It represent
s the minimum oxygen
concentration required for the test piece to continue burning in mixed gas of oxygen and nitrogen. When the value is
higher, the fire retarding property is higher. Since the oxygen concentration in the air is 21%, a plastic with an
oxy
gen index greater than 22 has self
-
extinguishing property, while a plastic with oxygen index smaller than 21 is
flammable.




Fire Resistance

-

Boru Kısmında Koymak Daha İyi Olabilir


Sonuçta burada üründen değil maddeden bahsediyoruz

Fires and
explosions in sewers in urban areas are not unusual (Philibin and Vickery, 1993).


Sewer pipes are subjected to fire hazards that can be initiated in sewage containing industrial chemicals and liquid
hydrocarbons, or as a result of traffic accidents involv
ing fire and gasoline spillage.


Concrete pipe doesn’t support combustion, and can withstand extremely high temperatures. Numerous incidences
of fires in sewer consturcted with concrete pipe have occurred. The pipe sustained little or no damage (Ohia
Concr
ete Pipe Association, 1979).


Steel is also a nonflammable material. However, petroleum
-
based lilings and coating materials, such as asphalt,
bitumen, plastics, and coal tar, used for corrosion protection of corrugated pipes, are flammable (ACPA, 1992; Ohi
o
Concrete Pipe Association, 1979). In a hostile fire environment, steel pipe can suffer damage from burning linings
and coatings.


Both PVC and HDPE pipes will burn where the air flow is adequate such as in culverts, storm drains and sewers
(Smith and
Brady
-
Williamson, 1997; ACPA, 1983;Chambers and Heger, 1980), although PVC has been identified as a
material with one of the lowest flammability ratings among common plastics (Curtis, 1977). Other concerns include
the evaluation of acidic fumes and smoke t
hat accompany therman degradation, when plastics are exposed to fire.


HDPE deforms at temperatures above 120°C and melst completely at 135°C. Polyethylene burns when exposed to a
flame, because it is a hydrocarbon (PPI, 1993). HDPE pipe has been recognize
d as a fire hazard and is therefore not
recommended for use in drain and sewer systems, because of the difficulty of fire control, confinement and
extinguishment (Philbin and Vickery, 1993). In a flammibility test carried out by the North Carolina Departme
nt of
Transportation (1991), one end of a corrugated HDPE culvert pipe was exposed to fire, and within 1 minute, the pipe
was engulfed in flames. The pipe was observed to fuel the fire, and burn continuously throughout its entire length.
Conclusion: any ap
plication where the ends of HDPE pipe are exposed, such as culvert applications, makes it
susceptible to fire damage (North Carolina Department of Transportation, 1991).


According to ACPa (1982), the Hardwood Plywood Manufacturers Association conducted in
dependent fire resistance
testing according to ASTM E 84. Reinforced
-
concrete and corrugated steel pipes with asphalt lining and coating,
corrugated steel pipes with asphalt lining and coating, corrugated steel pipe with polymeric lining and coating, rib
-
w
alled PVC pipe, PVC solid
-
walled pipe and rib
-
wallled PVC pipe, PVC solid
-
walled pipe and rib
-
walled HDPE pipe
were inclded in the comparative fire testing. (two other pipes included in the testing were corrugated aluminum pipe
and ABS pipe.) Below table s
ummerizes, in part, the fire resistance characteristics of the tested pipe materials (ACPA,
1982). The higher the flame spread index, the lower the fire resistance (ASTM E 84
-
94).
7


Material

Flame
Spread Index

Smoke
Density Index

Fire Resistance
Ranking*

Concrete pipe

0

0

6 (best)

Rib
-
walled PVC sewer pipe

10

10

5

PVC sewer pipe

20

330

4

CSP with polymeric coating

35

580

3

Rib
-
walled HDPE pipe

60

820

2

CSP with asphalt coating

880

860

1

* Fire resistance ranking, not in the original table, is
added to indicate relative
fire resistance performance. The best performance ranks the highest.


Durability

& Service Life

Resistance to oxidation by atmospheric oxygen influences the durability of a material the most (under normal
conditions). PVC is
highly resistant to oxidative reactions and maintains its performance for a long time, because the
chlorine atom is bound to every other carbon chain in its molecular structure. Since the other general purpose
plactics with structures made up only of carbo
n and hydrogen are more susceptible to deterioration by oxidations in
extended use conditions.


Measurements on underground 35 year
-
old PVC pipes taken by the Japan PVC Pipe & Fittings Association showed no
deterioration and the same strength as new pipes
.


Research in Germany (60 Jahre Erfahrungen mit Rohrleitungen aus Weichmachfreiem PVC, 1995, KRV) has shown
that soil buried pipes dug up after 60 years of active use when analysed were proven to be fit for purpose and likely
to have a further life expecta
ncy of 50 years!


Oil/Chemical resistance

Since the main chain of the polymer is made by single bonds of carbon atoms, PVC has excellent chemical resistance,
as with other general
-
purpose plastics such as PE, PP, or PS.
PVC is resistant to acid, alkali an
d almost all inorganic
chemicals. Although PVC swells or dissolves in aromatic hydrocarbons, ketones, and cyclic ethers, PVC is hard to
dissolve in other organic solvents.


For the sewage pipes produced with PVC material

The source of the chemicals in
sewage varies, depending on whether the pipe is used to transport industrial or
domestic sewage.


In domestic sewers, the pipe may be subjected to chemicals and processes such as;



Hydrogen sulfide



Sulfruric acid



Chloride ions



Sulfate ions



Lime leaching



Ca
rbonation

In industrial sewers, the pipe may be subjected to;



Acids



Alkali



Organic chemicals such as aromatics and hydrocarbons



Industrial wastes

Depending on locations, the soils may contain chemicals, suh as;



Chloride ions



Diluted acids,



Soil chemicals,



Bacteria (bio
-
corrosion)


The resistance of a pipe to physical, chemical and other forms of attack varies because of the differences in material
characteristics. For exampla, steel pipe is always subjected to corrosion when not protected, whereas concrete
pipe
may suffer
severe deterioration because of sulfate attack. Plastic pipe may degrade because of exposure to certain
solvents. Various
influences on the durability of different pipes are reviewed.


Comparison of Resistance Characteristics

The long
-
term
performance and durability of sewer pipes are directly related to their resistance to various chemical
and biological attacks. Sources and concentrations of chemicals in sewage can vary depending on whether the sewer
carries industrial or domestic effluent
. On the other hand, soils in certain geographic areas are known to contain high
concentrations of sulfates.


In general, concrete and corrugated steel pipes are more vulnerable to chemical attack than PVC and HDPE pipes.
High resistance to chemical attack

is the most attractive feature regarding the use of plastic pipes in sewer systems.
Corrososion susceptibility of the four pipe materials is shown on the table below.


Corrosion Type

Pipe

Reinforced
-
Concrete

Steel

HDPE

PVC

Acid Corrosion






(Note 1)


Sulfate Ion Corrosion






Chloride Ion Corrosion







Leaching






Bacteria Induced Corrosion






(Note 2)


(Note 2)

Certain Solvents




(Note 1)


(Note 3)

Environmental Stress Cracking









Notes:





1. HDPE pipe is stable in the presence of most acids and bases. However, it is affected by apolar solvents and chemicals, suc
h
as petroleum product and gasoline. Long
-
r
erm exposure to low concentrations of sulfuric acid may also affect the properties
of HD
PE.

2. Both PVC and HDPE pipes have high resistance to bacteria attack. However, some additives in these plastic materials
promote bacteria growth and cause biodegration of the materials.

3. PVC pipe has good resistance to most chemical attacks,
except aromatic or chlorinated hydrocarbons, ketones
,

esters
,
alcohols, ethers and strong alkalies.


Furthermore, the chemical substances that spira pipes have resistance, but concrete pipes are harmfully affected are
listed below.



Acidic liquids



Free
mineral acids such as; sulphuric acid, hydrochloric acid, nitric acid etc.



sulphur dioxide



hydrogen sulphur



free organic acids such as; acetic acid, lactic acid etc.



descaling agent carbonic acid



ammonium salts



magnesium salts



sulphates



district canalisati
on waste water & industrial waste water



rain water & undergound water



sea water & river water



mountain water & spring water & marsh water

For more information about the chemical substances and their affects, please contact Novaplast authorized
personel.


Strength

PVC is extensively used for municipal water supply/sewage pipes, spouts, profiles, etc., since its mechanical
properties such as tensile strength and tensile modulus are better than those of other general purpose olefin
plastics, and these
products are robust and durable. In comparison to general purpose pipes, uPVC has better;



Tensile strength



Tensile modulus



Bending strength



Fatigue strength


Creep Properties

Plastic products are said to show a ‘creep behaviour’, where the product is def
ormed

(by an amount roughly
predictable by the flexural modulus of the plastic)

at room temperature as time elapses when an external force is
applied continuously
. After the external force is removed, the part will partially recover its original dimensions
, but
depending on the material, some portion of the deformation will remain permanently. This non
-
recoverable
deformation is called creep.


Under normal environmental conditions, rigid PVC products show very little creep and are superior in comparison
wit
h other plastic products such as PE or PP.
The table below shows the minimum creep modulus of HDPE, PP and
uPVC, the bigger is the creep modulus value, the lower is the creep.



Density

The true specific gravity of PVC is about 1.4, which is comparatively heavy among plastics. This can be a disadvantage
depending on the application.


Vicat Softening Temperature

The heat distortion temperature is the temperature when the test piece placed

in the heat medium with bending
load applied reaches a specified deflection as temperature rises. The Vicat softening temperature is defined as the
temperature where the needle shaped penetrator sinks into the test piece to a specified depth as temperatur
e of
the heating medium rises and specified vertical load is applied to the test piece. The lower the measured value in C°
the higher the rigity.



Environmentally Friendly



It is 100% recycble.
Thermoplastic resins can be re
-
softened by heating and then
can be re
-
used as other
plastics.




PVC is made of 43% carbon (derived predominantly from oil/gas via ethylene) and 57% chlorine (derived
from industrial gas). PVC is a
natural resource saving plastic

(less negative impact on the environment)
because it is
less dependent than other polymers on crude oil or natural gas (which is nonrenewable).



Resistance to oxidation by atmospheric oxygen influences the durability of a material the most (under
normal conditions). PVC is highly resistant to oxidative reactions

and maintains its performance for a long
time, because the chlorine atom is bound to every other carbon chain in its molecular structure.


Avoids Poising

Most of the poisonings during fire usually occurs because of the Carbon Monoxide (CO) gas produced
from non
-
combustible products.
Because CO

is odorless and highly toxic gas, people are poisoned without being able to
realize

the presence of carbon monoxide.


When PVC burns, it produces hydrocen chloride (HCl) gas. Thanks to the pungent smell, even its
5 PPM in the
environment, it makes people realize the smell and move away from that environment immediately. Accordingly
avoids people to be poisoned.


The below table shows the amount of gas produced when 1 gram of the stated material burns.


While burning, PVC produces HCl, CO2, CO gasses. It doesn’t produce as dangerous and carcinogenic gases. Even CO
gas, which
is produced by all plastics, is produced less with respect to others.


Linear Expansion

While the pipes produced from the raw materi
als such as HDPE, PP and PVC are used for transportation of
industrially purposed hot water thermal expansion occurs, which causes elongation in the length of the pipes.


In such projects, the value of the liquid temparature to be moved must be take into a
ccount in accordance with the
following “linear expansion” formula.



FORMÜL

Formüldeki simgelerin açılımları

Bazı plastik hammaddelerin genleşme katsayıları
tablo


As it is seen on the table alove, coefficient of linear expansion of PVC is mostly very
lower than the other polymers.



PVC
-
U PHYSICAL & MECHANICAL PROPERTIES

PROPERTY

APROXIMATE VALUE

Density (g/cm
3
)

1.3

1⸴5

周敲T慬⁣ondu捴楶楴y
圯(m·
O


0⸱.

0.28

呥n獩V攠V瑲敮W瑨
MP愩a





呥n獩V攠modu汵猠VMP愩

3000
-
4000

䙬數u牡r⁳ r敮e瑨W
⡹i敬e⤠(MP愩


-
100

呥n獩V攠䕬Nng慴aon⁡ ⁢牥慫
┩

㌱3
-



䍯mp牥獳ron⁳ r敮e瑨
MP愩



䍯敦晩捩敮琠o映fh敲e慬⁥apan獩Vn
汩n敡爩⁛ mI(mm₰䌩]

7휱0
−5

D慭p楮g⁉mp慣a⁓瑲敮 瑨
歊km2)


-



噩捡琠䈠Bo晴fn楮g 瑥mp敲慴u牥r⢰䌩



100

H敡e D敦汥捴楯n
呥mp敲e瑵牥r⢰(⁡ ′64p獩V

140
-
170

Resistivity (Ω m)

1016

Surface resistivity (Ω)


13


14

Specific Heat Capacity (kJ/kg
-
1

K
-
1
)

2.15
-
2.16

Glass Transition Temperature (°C)

87

Service Temperature in the Long Term (°C)

-
25
-
80 (recommended maximum heat
is 70°C)


Where;

(
Katalogta kullanılabilir….
) TANIM YERİNE TABLOYU OKUSAK DAHA İYİ DEĞİL Mİ

Thermal conductivity
: In physics, thermal conductivity, k, is the property of a material's ability to conduct heat.

Tensile strength
: The yield strength or yield
point of a material is defined in engineering and materials science as the
stress at which a material begins to deform plastically.

Tensile modulus
: Tensile modulus is a measure of the stiffness of an elastic material and is a quantity used to
characterize

materials.

Flexural strength
: Flexural strength, also known as modulus of rupture, bend strength, or fracture strength,[dubious


discuss] a mechanical parameter for brittle material, is defined as a material's ability to resist deformation under
load.

T
ensile Elongation at break
: The elongation
-
to
-
break is the strain on a sample when it breaks. The elongation
-
to
-
break sometimes is called the ultimate elongation. The combination of high ultimate tensile strength and high
elongation leads to materials of h
igh toughness.

Compression strength
: Compressive strength is the capacity of a material or structure to withstand axially directed
pushing forces. When the limit of compressive strength is reached, materials are crushed.

Coefficient of thermal expansion
: T
hermal expansion is the tendency of matter to change in volume in response to a
change in temperature
.
Materials which contract with increasing temperature are rare; this effect is limited in size,
and only occurs within limited temperature ranges.

Damping

Impact Strength
: Impact energy is a measure of the work done to fracture a test specimen. When the
striker impacts the specimen, the specimen will absorb energy until it yields. At this point, the specimen will begin to
undergo plastic deformation at the
notch. The test specimen continues to absorb energy and work hardens at the
plastic zone at the notch. When the specimen can absorb no more energy, fracture occurs.

Resistivity
:
a.k.a.

electrical

resistivity, specific electrical resistance, or volume resis
tivity) is a measure of how strongly
a material opposes the flow of electric current. A low resistivity indicates a material that readily allows the
movement of electric charge.

Surface resistivity
:

is
the resistance to the flow of electrical current acros
s its surface. This is in contrast to the
volume resistivity (or simply electrical resistivity), which is the resistance to flow through the three
-
dimensional
volume of a sample. The higher the surface/volume resistivity, the lower the leakage current and
the less conductive
the material is.

Specific heat capacity
: The specific heat capacity of a solid or liquid is defined as the heat required to raising unit
mass of substance by one degree of temperature. The units of specific heat capacity are J oC
-
1 g
-
1
or J K
-
1 g
-
1

Glass Transition Temperature: The glass transition temperature (Tg) of a non
-
crystalline (amorphous) material is the
critical temperature at which the material changes its behavior from being 'glassy' to being 'rubbery'. 'Glassy' in this
co
ntext means hard and brittle (and therefore relatively easy to break), while 'rubbery' means elastic and flexible.



COMPARISON OF SOME PROPERTIES OF PLASTIC DRAINAGE PIPE MATERIALS

CHRACTERISTIC

PVC
-
U

PP

PE
-
HD

UNIT

Avarage Density

2.15
-
2.16

900

940

g/cm
3

Avarage Coefficient of thermal expansion (linear)

7×10
−5

14×10
−5

17×10
−5

mmI(mm₰䌩
孭洯[mm⁋⥝

周敲T慬⁣ondu捴楶楴y

0⸱.

0⸲

0⸳.
-
0⸵0

圯(m띋·

印散楦楣⁈敡e⁃慰慣 Wy

2⸱.
-
2⸱6

2

2⸳
-
2.9

歊k歧
-
1

K
-
1

Surface resistivity

>10
13

>10
12

>10
13

Ω

H敡e
D敦汥捴楯n⁔emp敲e瑵牥r⡌o慤:‱8⸶.歧kcm
2
)

54
-
80

57
-
64

43
-
49

°C

Poisson ratio

0.4

0.42

0.45

-

Modulus of Elasticity, E (1min)

≥3000

≥1250

≥800

MPa

P.S. You can see also DIN 16961
-
2 Table 3 comparison of creep modulus values.


ADVANTAGES zaten
properties’in içinde…üründe madde madde yazmak daha doğru