Introduction to Textile Materials
Science
Dr,Yiping Qiu
邱夷平
Donghua University
Course Syllabus
? Textbook
– Kathryn L,Hatch,Textile Science,West
Publishing Company,1993.
? Reference book
– Yao,M,et,al,Textile Materials (in Chinese),
2nd ed.,Textile Industry Publishing House,
1990
Justification
? Textile materials are the basic materials,It
is crucial to establish a basic understanding
of the science governing the behavior of
these materials,
? The course is taught in a bilingual system
such that the students will have an
opportunity to enhance their English ability
while learning the key knowledge in textiles,
Grading
? Grades for this course are determined by
– homework (10%),
– two tests (30% each) and
– one final exam (30%),
The final grade will be from A to F
corresponding to the total score according to
the student handbook,
Attendance
? Attendance is mandatory,
? A class roll will be taken at the beginning of each
class,
? Missing every three times without reasonable
excuses in the semester will have course grade
deducted 10 points or one letter grade,
? A perfect attendance record will be rewarded 5
points in their total course grade,
Honor Code
? Students will be expected to adhere to the
guidelines for academic integrity,That
means that ANY action that goes against the
rules set forth when giving homework or
test or taking class roll will be dealt with in
a very strict fashion,
? Grades are valuable,honor and integrity are
priceless,
Topical Outline
Su b j ect N o,
L ect u res
1,In t ro d u ct i o n,cla s s i fi cat i o n an d d efi n i t i o n o f fi b ers 4
2,Mo l ecu l ar,m i cro an d m acr o s t ru ct u res o f fi b ers 4
3,Mo rp h o l o g i cal p ro p ert i es o f fi b ers 4
4,Mo i s t u re ab s o rp t i o n p ro p ert i es o f t ex t i l es 4
5,Mech an i cal p ro p ert i es o f fi b ers 6
6,Fi rs t t es t ( O ct, 15 ) 1
7,T h erm al,op t i cal,and el ect ri cal p ro p ert i es o f fi b ers 6
8,S t r u ct u re s,p rope rt i es,a n d i d e n t i f i c at i o n o f
co m m o d i t y te x t i l e fi b ers
6
9,Cl as s i fi cat i o n an d s t ru ct u re o f t ex t i l e y arn s 4
10,S t ru ct u ral p ara m et ers o f t ex t i l e y arn s 6
11,Mech an i cal p ro p ert i es o f t ex t i l e y arn s 2
12,Seco n d t es t ( D ec,1 ) 1
13,Cl as s i fi cat i o n o f t ex t i l e fab ri cs 4
14,Per fo rm an ce p ro p ert i es o f fab ri c fo r ap p are l s 6
15,T ex t i l e t es t i n g an d q u al i t y ev al u at i o n 4
16,Fi n al t es t
Introduction
? Reading assignment
– Textbook,Kathryn L,Hatch,Chapter 7,Textile
Science,West Publishing Company,New York,
USA
– Handouts when available.
Introduction
? Expectations
– At the conclusion of this section,you should be
able to:
? Classify fibers
? Describe spinning processes for fibers
? Describe application and future development of
fiber industry
Introduction
? What is a fiber?
– Large length to width ratio
– Small enough to be flexible
? Textile fibers
– Minimum length,12.5 mm,desirable,>20 mm.
– Strong enough to be processed
Classification of fibers
? Polymeric
? Inorganic
? Engineered
? Unconventionally shaped
Classification of fibers
? Polymeric
– Natural fibers
? cotton
? wool
? silk
? others,flex,jute,ramie,hemp
Classification of fibers
? Polymeric
– Regenerated fibers
? History,
– invented in 1890’s by Schoenbein
– Commercially available in 1896
? Examples
– Vicose Rayon
– Cellulose acetate
– Cellulose triacetate
– Lycel
Classification of fibers
? Polymeric
– Synthetic fibers
? History
– Wallace Carothers at du Pont invented a series of polymers
? Major types
– Polyester
– Polyamide
? Nylons
? Aromatic
? Kevlar
? Nomax
Classifications of fibers
? Polymeric
? Acrylic (copolymers of PAN and other vinyl polymers)
? Modacrylic
? Polyolifin
– Polyethylene
– Polypropylene
? Elastomeric
– Spandex (polyurethane)
? Polyvinyl alcohol
? Polyvinyl chloride
Classifications of fibers
? Inorganic
– Natural
? asbestos
– Manmade
? glass
? carbon/graphite
? ceramic
? metal
Classifications of fibers
? Engineered fibers
? Bicomponent fibers,
? Sheath-core
? Side by side
? Island in sea (matrix fibril)
? Citrus
? Unconventionally shaped
– 4DG
– Hollow
Fibers and their properties
? Natural protein fibers
– high resilience
? ability to do work against restraining forces during
returning from deformed state
– Hygroscopic or hydrophilic
? likes water and absorbs water
– High heat of wetting
– Most mechanical properties change when
absorbing water
Fibers and their properties
? Natural protein fibers
– Harmed by alkalis,e.g,NaOH
– Harmed by chlorine bleach & perspiration
– Weakened & yellowed by UV light
– Not readily flammable
Fibers and their properties
? Natural cellulose fibers
– High moisture absorption
– Mechanical properties change up on water
absorption
– Swells in water but reversible upon drying
– High resistance to alkaline degradation
– Low resilience
Fibers and their properties
? Manufactured cellulose fibers
– Low tenacity
– Much weaker when wet than dry
– Low abrasion resistance
– Medium resistance to UV light
– Dry cleaning or gentle cycle
Fibers and their properties
? Synthetic fibers
– Low moisture regain
– Lowest softening temperatures
– Highly oleophilic (love oil) & hydrophobic (hate water)
– Highest electrical resistivity
– Highest toughness
– Medium to high resilience
– High resistance to moths,meldew & fungi
Chapter 7
Fiber Morphology and Formation
? Morphology
– Study of size,shape,and structure of fibers
? Macrostructure
– Features which are discernible by human eyes.
? length,Staple or filament
? size,wide range from <5 to >70?m
Chapter 7
Fiber Morphology and Formation
? Measurement of fiber size
? Gravimetric,cut and weigh
? weight/length
? length/weight
? Microscopic
? Manual
? Vibroscope (a machine that measures
vibration frequencies of fibers
subjected to certain tension)
Chapter 7
Fiber Morphology and Formation
? What to measure
?Specific surface,Surface area/unit volume
– For uniform fibers of any cross-section:
ss = perimeter/cross-section area
for round fibers,
drr
r
ss
422
2 ??? ?
?
Chapter 7
Fiber Morphology and Formation
?Linear density
– Direct,weight based,continuous fibers
and yarns (Mass/unit length)
? denier ( den,Nd ),grams/9000m
? tex ( tex,Nt ),grams/1000m
? decitex ( dtex,Ndt ),grams/10,000m
– As fiber/yarn # ?,fiber/yarn diameter ?
– For any direct system
l
WS =
N D I R
Chapter 7
Fiber Morphology and Formation
– Indirect,Length based,staple fibers
? Cotton count
?Nc = # of 840 yd hanks/lb
? Worsted count
?Nw = # of 560 yd hanks/lb.
?Woolen count
?Nwr= # of 1600 yd hanks/lb
? As yarn # ?,yarn diameter ?
? For any indirect system
WS
l = N
I N D
Chapter 7
Fiber Morphology and Formation
D i re ct Sy st e m l u n i t s W u n i t s S
N d me t e rs g ra ms 9000 m / g
N t me t e rs g ra ms 1000 m / g
N dt me t e rs g ra ms 10000 m / g
I n d i re ct Sy st e m
N e y a rd s pounds 840 y d/ l b
N w y a rd s pounds 560 y d/ l b
N wr y a rd s pounds 1600 y d/ l b
Chapter 7
Fiber Morphology and Formation
? Calculation of diameter from linear density
? Direct systems
S
N4 = d D I R
??
Chapter 7
Fiber Morphology and Formation
? Calculation of diameter from linear density
? Indirect systems
SN
4
= d
I N D??
Chapter 7
Fiber Morphology and Formation
? Example 1
gcmgmS
cmg
N d
/000,900/000,9
/38.1
15
3
??
?
?
?
S
Nd d
??
4?
)/(000,900)/(38.114.3
154
3 gcmcmg ??
??
mcm ?2.390 0 3 92.0 ??
Chapter 7
Fiber Morphology and Formation
? Example 2
lbydScmgN e /8 4 0 /55.1 25 3 ??? ?
SN
d
e??
4?
yd
cm
g
lb
lb
yd
cm
g
44.91
454
1
8402555.114.3
4
3
?????
?
mcm ?13 901 39.0 ??
Chapter 7
Fiber Morphology and Formation
? Example 3
– Calculate linear density from diameter
i n t e x?d e n s i t y l i n e a r is w h a t 910 100 31 g / c m.ρmd ?? ?
gcmgmS /0 0 0,1 0 0/1 0 0 0 ??
2
3 1 0 0 0 0
11 0 00 0 0,1 0 091.014.3
4
1
???
?
???
? ??????
m
cmm
g
cm
cm
g
?
?
4
2Sd
N t ???
te x15.7?
Chapter 7
Fiber Morphology and Formation
? Example 4
– Calculate linear density from diameter
c o u n t?c o t t o n 910 100 31 g / c m.ρmd ?? ?
gcmglbydcmlbydlbydS /18.169454 144.91840/840 ?????
2
3 10000
1
10018.16991.014.3
4
??
?
?
??
?
?
????
?
m
cm
m
g
cm
cm
g
?
?
7.82?
2
4
SdN e ???
Chapter 7
Fiber Morphology and Formation
? Example 5
– Calculate fiber linear density from length and weight
,,;250 W;20 etd NNNg.ml ??
5.1 1 220 /9 0 0 025.0 ???? m gmglWSN d
5.1220 /100025.0 ???? m gmglWSN t
3934.39
4 5 4
1
91.0
1
8 4 025.0
20
??
???
??
g
lb
yd
m
lb
yd
g
m
WS
l
N e
Chapter 7
Fiber Morphology and Formation
? Example 6
– Calculate specific surface of the above two fibers
cmd 0 0 3 9 2.01 ?
14.1020
00392.0
44 ???? cm
cmdss
cmd 0 1 8.01 ?
12 22
0 18.0
44 ???? cm
cmdss
Chapter 7
Fiber Morphology and Formation
? Dimensional parameters relevant only
to cotton:
– Maturity,thick,well developed cell wall is
mature
– Immaturity ratio,
xA
AI 0?
A
A x
0
A x = a c t u a l c r o s s - s e c t io n a r e a o f f ib e r
A 0 = a r e a if p e r ime t e r w a s c ir c le
Chapter 7
Fiber Morphology and Formation
? Fibers in textured yarns
?Crimp,2-D or 3-D waviness along fiber length
? Crimp affects
? Cover
? Bulk
? Insulation
? Extensibility
? Hand
? Cohesion
? Light reflection/luster
Chapter 7
Fiber Morphology and Formation
? Textured yarns
? Natural fibers,natural crimp
? Manufactured fibers,crimped by texturing
processes
Chapter 7
Fiber Morphology and Formation
? Microstructures,
– Features can be observed by optical
microscope.
? Surface contour/longitudinal form
smooth striated convoluted serrated
pitted lobed scaly
? Cross-sectional area shape
round kidney bean triangular
flat dog-bone multi-lobal
Chapter 7
Fiber Morphology and Formation
? Submicroscopic structure
?Features may be observed by electron
microscope.
? Natural fibers,distinct layers
? Manufactured and silk,uniform throughout
except skin-core effect
Chapter 7
Fiber Morphology and Formation
? Fine structure (molecular level)
? Description of polymers composing fibers
?molecular length,(degree of polymerization)
?width,shape,chemical composition,and
arrangement of polymers and bonds which hold
them together
Chapter 7
Fiber Morphology and Formation
? Polymers,
?(macromolecules) composed of covalent-
bonded structural units (monomers)
? Types:
– Homopolymers
– Copolymers
– Block polymers
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Types:
? Linear
? Branched
? Network
(cross-linked)
L i n e a r
B r a n ch e d
Ne tw o r k
( cr o ss - li n ke d )
Chapter 7
Fiber Morphology and Formation
? Polymers,
? Chemistry
?Backbones,-C-C-,-C-O-C-,-C-N-C-
?Configuration
?Side groups,-H,-CH3,-OH
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Orientation and Crystallinity
?Highly oriented,large proportion of polymer
chains are aligned with the fiber axis
?Crystalline regions,adjacent polymers are
packed with spatial order
?Amorphous regions,no spatial order
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Intermolecular forces
? Difference in electronegativity of the two atoms
forming a covalent bond,
? The large the difference,the more polar the bond.
? Extremely large difference leads to ionic bond.
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Intermolecular forces
Bonds Boning Energy
?Van der Waals forces 4-8kJ/mole
?Dipole-dipole bonds 20kJ/mole
?Hydrogen bonds 40kJ/mole
?Ionic bonds >650kJ/mole
?Covalent bonds >150kJ/mole
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Two types of polymerization:
? Step growth or condensation polymerization
? Chain or addition polymerization
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Step growth or condensation polymerization
? Example
CO 2 H + H O C H 2 CH 2 OHHO 2 C
te r ep ht ha li c ac i d et hy l e ne g l yco l
C O C H 2 CH 2 O + 2 H 2 OC
P ol y ( et hy l ene t er eph tha l ate )
O
T
e
O
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Characteristics of step growth
polymerization
? formation of each covalent bond in polymer
chain is accompanied by releasing of small
byproduct molecules,such as H2O.
? dependent upon the collisions of reactive end
groups.
? high consumption of monomers but slow
molecular weight increase
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Addition polymerization
? Example,polyethylene
Initiation,
R? + CH2=CH2 ? RCH2CH2 ?
Propagation
RCH2CH2 ? + CH2=CH2 ? RCH2CH2CH2CH2 ?
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Characteristics of addition polymerization
? require highly reactive initiator species to begin
successive addition of monomers
? no small molecules released
? relatively low reaction rate
? reaction can last till very high molecular weight (DP)
? termination required to control DP
? three stages,initiation,propagation,and termination
Chapter 7
Fiber Morphology and Formation
? Manufactured fiber formation
– Fiber spinning,extruding polymer melts or
solution through a spinneret with up to
thousands of holes
Chapter 7
Fiber Morphology and Formation
? Melt spinning
– The raw material
? has to have a melting temperature
– Thermoplastic polymers or glass,
e.g,polyester and nylon
– Process:
Chapter 7
Fiber Morphology and Formation
? Dry spinning
– Raw materials
? For polymers with no melting temperature,solvent
is used to make a solution of the polymer
? solvents must be able to evaporate quickly
– e.g,acetate triacetate and some aramid fibers
– Process
Chapter 7
Fiber Morphology and Formation
? Wet spinning
– Raw materials
? For polymers with no melting temperature,solvent
is used to make a solution of the polymer
? Coagulation bath is required
– e.g,Rayon and acrylic
– Process
Chapter 7
Fiber Morphology and Formation
? Other spinning methods
– Reaction spinning
? Polymerization occurs during extrusion through the spinneret
?hot air solidifies the filaments
e.g,some Spandex fibers
– Gel spinning
? Extra high molecular weight polymers
? dilute,highly viscous polymer solution
? fluid when extruded out but form a gel at room temperature
e.g,Spectra (polyethylene)
Wallace H,Carothers (1896-1937)
? Inventor of nylon and
neoprene rubber
? Graduated from
University of Illinois
? Professor at Harvard
University
? Leading scientist at du
Pont
Bicomponent fibers
4DG fiber Hollow fiber
Science
Dr,Yiping Qiu
邱夷平
Donghua University
Course Syllabus
? Textbook
– Kathryn L,Hatch,Textile Science,West
Publishing Company,1993.
? Reference book
– Yao,M,et,al,Textile Materials (in Chinese),
2nd ed.,Textile Industry Publishing House,
1990
Justification
? Textile materials are the basic materials,It
is crucial to establish a basic understanding
of the science governing the behavior of
these materials,
? The course is taught in a bilingual system
such that the students will have an
opportunity to enhance their English ability
while learning the key knowledge in textiles,
Grading
? Grades for this course are determined by
– homework (10%),
– two tests (30% each) and
– one final exam (30%),
The final grade will be from A to F
corresponding to the total score according to
the student handbook,
Attendance
? Attendance is mandatory,
? A class roll will be taken at the beginning of each
class,
? Missing every three times without reasonable
excuses in the semester will have course grade
deducted 10 points or one letter grade,
? A perfect attendance record will be rewarded 5
points in their total course grade,
Honor Code
? Students will be expected to adhere to the
guidelines for academic integrity,That
means that ANY action that goes against the
rules set forth when giving homework or
test or taking class roll will be dealt with in
a very strict fashion,
? Grades are valuable,honor and integrity are
priceless,
Topical Outline
Su b j ect N o,
L ect u res
1,In t ro d u ct i o n,cla s s i fi cat i o n an d d efi n i t i o n o f fi b ers 4
2,Mo l ecu l ar,m i cro an d m acr o s t ru ct u res o f fi b ers 4
3,Mo rp h o l o g i cal p ro p ert i es o f fi b ers 4
4,Mo i s t u re ab s o rp t i o n p ro p ert i es o f t ex t i l es 4
5,Mech an i cal p ro p ert i es o f fi b ers 6
6,Fi rs t t es t ( O ct, 15 ) 1
7,T h erm al,op t i cal,and el ect ri cal p ro p ert i es o f fi b ers 6
8,S t r u ct u re s,p rope rt i es,a n d i d e n t i f i c at i o n o f
co m m o d i t y te x t i l e fi b ers
6
9,Cl as s i fi cat i o n an d s t ru ct u re o f t ex t i l e y arn s 4
10,S t ru ct u ral p ara m et ers o f t ex t i l e y arn s 6
11,Mech an i cal p ro p ert i es o f t ex t i l e y arn s 2
12,Seco n d t es t ( D ec,1 ) 1
13,Cl as s i fi cat i o n o f t ex t i l e fab ri cs 4
14,Per fo rm an ce p ro p ert i es o f fab ri c fo r ap p are l s 6
15,T ex t i l e t es t i n g an d q u al i t y ev al u at i o n 4
16,Fi n al t es t
Introduction
? Reading assignment
– Textbook,Kathryn L,Hatch,Chapter 7,Textile
Science,West Publishing Company,New York,
USA
– Handouts when available.
Introduction
? Expectations
– At the conclusion of this section,you should be
able to:
? Classify fibers
? Describe spinning processes for fibers
? Describe application and future development of
fiber industry
Introduction
? What is a fiber?
– Large length to width ratio
– Small enough to be flexible
? Textile fibers
– Minimum length,12.5 mm,desirable,>20 mm.
– Strong enough to be processed
Classification of fibers
? Polymeric
? Inorganic
? Engineered
? Unconventionally shaped
Classification of fibers
? Polymeric
– Natural fibers
? cotton
? wool
? silk
? others,flex,jute,ramie,hemp
Classification of fibers
? Polymeric
– Regenerated fibers
? History,
– invented in 1890’s by Schoenbein
– Commercially available in 1896
? Examples
– Vicose Rayon
– Cellulose acetate
– Cellulose triacetate
– Lycel
Classification of fibers
? Polymeric
– Synthetic fibers
? History
– Wallace Carothers at du Pont invented a series of polymers
? Major types
– Polyester
– Polyamide
? Nylons
? Aromatic
? Kevlar
? Nomax
Classifications of fibers
? Polymeric
? Acrylic (copolymers of PAN and other vinyl polymers)
? Modacrylic
? Polyolifin
– Polyethylene
– Polypropylene
? Elastomeric
– Spandex (polyurethane)
? Polyvinyl alcohol
? Polyvinyl chloride
Classifications of fibers
? Inorganic
– Natural
? asbestos
– Manmade
? glass
? carbon/graphite
? ceramic
? metal
Classifications of fibers
? Engineered fibers
? Bicomponent fibers,
? Sheath-core
? Side by side
? Island in sea (matrix fibril)
? Citrus
? Unconventionally shaped
– 4DG
– Hollow
Fibers and their properties
? Natural protein fibers
– high resilience
? ability to do work against restraining forces during
returning from deformed state
– Hygroscopic or hydrophilic
? likes water and absorbs water
– High heat of wetting
– Most mechanical properties change when
absorbing water
Fibers and their properties
? Natural protein fibers
– Harmed by alkalis,e.g,NaOH
– Harmed by chlorine bleach & perspiration
– Weakened & yellowed by UV light
– Not readily flammable
Fibers and their properties
? Natural cellulose fibers
– High moisture absorption
– Mechanical properties change up on water
absorption
– Swells in water but reversible upon drying
– High resistance to alkaline degradation
– Low resilience
Fibers and their properties
? Manufactured cellulose fibers
– Low tenacity
– Much weaker when wet than dry
– Low abrasion resistance
– Medium resistance to UV light
– Dry cleaning or gentle cycle
Fibers and their properties
? Synthetic fibers
– Low moisture regain
– Lowest softening temperatures
– Highly oleophilic (love oil) & hydrophobic (hate water)
– Highest electrical resistivity
– Highest toughness
– Medium to high resilience
– High resistance to moths,meldew & fungi
Chapter 7
Fiber Morphology and Formation
? Morphology
– Study of size,shape,and structure of fibers
? Macrostructure
– Features which are discernible by human eyes.
? length,Staple or filament
? size,wide range from <5 to >70?m
Chapter 7
Fiber Morphology and Formation
? Measurement of fiber size
? Gravimetric,cut and weigh
? weight/length
? length/weight
? Microscopic
? Manual
? Vibroscope (a machine that measures
vibration frequencies of fibers
subjected to certain tension)
Chapter 7
Fiber Morphology and Formation
? What to measure
?Specific surface,Surface area/unit volume
– For uniform fibers of any cross-section:
ss = perimeter/cross-section area
for round fibers,
drr
r
ss
422
2 ??? ?
?
Chapter 7
Fiber Morphology and Formation
?Linear density
– Direct,weight based,continuous fibers
and yarns (Mass/unit length)
? denier ( den,Nd ),grams/9000m
? tex ( tex,Nt ),grams/1000m
? decitex ( dtex,Ndt ),grams/10,000m
– As fiber/yarn # ?,fiber/yarn diameter ?
– For any direct system
l
WS =
N D I R
Chapter 7
Fiber Morphology and Formation
– Indirect,Length based,staple fibers
? Cotton count
?Nc = # of 840 yd hanks/lb
? Worsted count
?Nw = # of 560 yd hanks/lb.
?Woolen count
?Nwr= # of 1600 yd hanks/lb
? As yarn # ?,yarn diameter ?
? For any indirect system
WS
l = N
I N D
Chapter 7
Fiber Morphology and Formation
D i re ct Sy st e m l u n i t s W u n i t s S
N d me t e rs g ra ms 9000 m / g
N t me t e rs g ra ms 1000 m / g
N dt me t e rs g ra ms 10000 m / g
I n d i re ct Sy st e m
N e y a rd s pounds 840 y d/ l b
N w y a rd s pounds 560 y d/ l b
N wr y a rd s pounds 1600 y d/ l b
Chapter 7
Fiber Morphology and Formation
? Calculation of diameter from linear density
? Direct systems
S
N4 = d D I R
??
Chapter 7
Fiber Morphology and Formation
? Calculation of diameter from linear density
? Indirect systems
SN
4
= d
I N D??
Chapter 7
Fiber Morphology and Formation
? Example 1
gcmgmS
cmg
N d
/000,900/000,9
/38.1
15
3
??
?
?
?
S
Nd d
??
4?
)/(000,900)/(38.114.3
154
3 gcmcmg ??
??
mcm ?2.390 0 3 92.0 ??
Chapter 7
Fiber Morphology and Formation
? Example 2
lbydScmgN e /8 4 0 /55.1 25 3 ??? ?
SN
d
e??
4?
yd
cm
g
lb
lb
yd
cm
g
44.91
454
1
8402555.114.3
4
3
?????
?
mcm ?13 901 39.0 ??
Chapter 7
Fiber Morphology and Formation
? Example 3
– Calculate linear density from diameter
i n t e x?d e n s i t y l i n e a r is w h a t 910 100 31 g / c m.ρmd ?? ?
gcmgmS /0 0 0,1 0 0/1 0 0 0 ??
2
3 1 0 0 0 0
11 0 00 0 0,1 0 091.014.3
4
1
???
?
???
? ??????
m
cmm
g
cm
cm
g
?
?
4
2Sd
N t ???
te x15.7?
Chapter 7
Fiber Morphology and Formation
? Example 4
– Calculate linear density from diameter
c o u n t?c o t t o n 910 100 31 g / c m.ρmd ?? ?
gcmglbydcmlbydlbydS /18.169454 144.91840/840 ?????
2
3 10000
1
10018.16991.014.3
4
??
?
?
??
?
?
????
?
m
cm
m
g
cm
cm
g
?
?
7.82?
2
4
SdN e ???
Chapter 7
Fiber Morphology and Formation
? Example 5
– Calculate fiber linear density from length and weight
,,;250 W;20 etd NNNg.ml ??
5.1 1 220 /9 0 0 025.0 ???? m gmglWSN d
5.1220 /100025.0 ???? m gmglWSN t
3934.39
4 5 4
1
91.0
1
8 4 025.0
20
??
???
??
g
lb
yd
m
lb
yd
g
m
WS
l
N e
Chapter 7
Fiber Morphology and Formation
? Example 6
– Calculate specific surface of the above two fibers
cmd 0 0 3 9 2.01 ?
14.1020
00392.0
44 ???? cm
cmdss
cmd 0 1 8.01 ?
12 22
0 18.0
44 ???? cm
cmdss
Chapter 7
Fiber Morphology and Formation
? Dimensional parameters relevant only
to cotton:
– Maturity,thick,well developed cell wall is
mature
– Immaturity ratio,
xA
AI 0?
A
A x
0
A x = a c t u a l c r o s s - s e c t io n a r e a o f f ib e r
A 0 = a r e a if p e r ime t e r w a s c ir c le
Chapter 7
Fiber Morphology and Formation
? Fibers in textured yarns
?Crimp,2-D or 3-D waviness along fiber length
? Crimp affects
? Cover
? Bulk
? Insulation
? Extensibility
? Hand
? Cohesion
? Light reflection/luster
Chapter 7
Fiber Morphology and Formation
? Textured yarns
? Natural fibers,natural crimp
? Manufactured fibers,crimped by texturing
processes
Chapter 7
Fiber Morphology and Formation
? Microstructures,
– Features can be observed by optical
microscope.
? Surface contour/longitudinal form
smooth striated convoluted serrated
pitted lobed scaly
? Cross-sectional area shape
round kidney bean triangular
flat dog-bone multi-lobal
Chapter 7
Fiber Morphology and Formation
? Submicroscopic structure
?Features may be observed by electron
microscope.
? Natural fibers,distinct layers
? Manufactured and silk,uniform throughout
except skin-core effect
Chapter 7
Fiber Morphology and Formation
? Fine structure (molecular level)
? Description of polymers composing fibers
?molecular length,(degree of polymerization)
?width,shape,chemical composition,and
arrangement of polymers and bonds which hold
them together
Chapter 7
Fiber Morphology and Formation
? Polymers,
?(macromolecules) composed of covalent-
bonded structural units (monomers)
? Types:
– Homopolymers
– Copolymers
– Block polymers
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Types:
? Linear
? Branched
? Network
(cross-linked)
L i n e a r
B r a n ch e d
Ne tw o r k
( cr o ss - li n ke d )
Chapter 7
Fiber Morphology and Formation
? Polymers,
? Chemistry
?Backbones,-C-C-,-C-O-C-,-C-N-C-
?Configuration
?Side groups,-H,-CH3,-OH
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Orientation and Crystallinity
?Highly oriented,large proportion of polymer
chains are aligned with the fiber axis
?Crystalline regions,adjacent polymers are
packed with spatial order
?Amorphous regions,no spatial order
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Intermolecular forces
? Difference in electronegativity of the two atoms
forming a covalent bond,
? The large the difference,the more polar the bond.
? Extremely large difference leads to ionic bond.
Chapter 7
Fiber Morphology and Formation
? Polymers,
– Intermolecular forces
Bonds Boning Energy
?Van der Waals forces 4-8kJ/mole
?Dipole-dipole bonds 20kJ/mole
?Hydrogen bonds 40kJ/mole
?Ionic bonds >650kJ/mole
?Covalent bonds >150kJ/mole
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Two types of polymerization:
? Step growth or condensation polymerization
? Chain or addition polymerization
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Step growth or condensation polymerization
? Example
CO 2 H + H O C H 2 CH 2 OHHO 2 C
te r ep ht ha li c ac i d et hy l e ne g l yco l
C O C H 2 CH 2 O + 2 H 2 OC
P ol y ( et hy l ene t er eph tha l ate )
O
T
e
O
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Characteristics of step growth
polymerization
? formation of each covalent bond in polymer
chain is accompanied by releasing of small
byproduct molecules,such as H2O.
? dependent upon the collisions of reactive end
groups.
? high consumption of monomers but slow
molecular weight increase
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Addition polymerization
? Example,polyethylene
Initiation,
R? + CH2=CH2 ? RCH2CH2 ?
Propagation
RCH2CH2 ? + CH2=CH2 ? RCH2CH2CH2CH2 ?
Chapter 7
Fiber Morphology and Formation
? Polymerization reactions:
– Characteristics of addition polymerization
? require highly reactive initiator species to begin
successive addition of monomers
? no small molecules released
? relatively low reaction rate
? reaction can last till very high molecular weight (DP)
? termination required to control DP
? three stages,initiation,propagation,and termination
Chapter 7
Fiber Morphology and Formation
? Manufactured fiber formation
– Fiber spinning,extruding polymer melts or
solution through a spinneret with up to
thousands of holes
Chapter 7
Fiber Morphology and Formation
? Melt spinning
– The raw material
? has to have a melting temperature
– Thermoplastic polymers or glass,
e.g,polyester and nylon
– Process:
Chapter 7
Fiber Morphology and Formation
? Dry spinning
– Raw materials
? For polymers with no melting temperature,solvent
is used to make a solution of the polymer
? solvents must be able to evaporate quickly
– e.g,acetate triacetate and some aramid fibers
– Process
Chapter 7
Fiber Morphology and Formation
? Wet spinning
– Raw materials
? For polymers with no melting temperature,solvent
is used to make a solution of the polymer
? Coagulation bath is required
– e.g,Rayon and acrylic
– Process
Chapter 7
Fiber Morphology and Formation
? Other spinning methods
– Reaction spinning
? Polymerization occurs during extrusion through the spinneret
?hot air solidifies the filaments
e.g,some Spandex fibers
– Gel spinning
? Extra high molecular weight polymers
? dilute,highly viscous polymer solution
? fluid when extruded out but form a gel at room temperature
e.g,Spectra (polyethylene)
Wallace H,Carothers (1896-1937)
? Inventor of nylon and
neoprene rubber
? Graduated from
University of Illinois
? Professor at Harvard
University
? Leading scientist at du
Pont
Bicomponent fibers
4DG fiber Hollow fiber
