TT 105 Final Exam

What is a textile?

a flexible fibrous structure

homopolymer

one type of repeat unit or mer

copolymer

two or more types of repeat unit or mer

mer

a single unit that makes up a polymer

polymer

a molecule that is made up of mer

thermoset

molecules that are set in stone once they cool down after being melted

can be melted several times and can be reshaped ; can be heated several times

intermolecular strong attraction

high melting temp, strong, stiff

intermolecular weak attraction

low melting temp, rubbery, flexible

ion-ion bond definition

transfer of electrons

ion-ion bond strength

very strong

covalent bond definition

electrons are shared between atoms

covalent bond strength

strong

hydrogen bonding strength

moderately strong

dipole-dipole bond strength

moderate

van der waals bond strength

weak

what type of interaction is in all molecules?

van der waals

degree of polymerization

total number of repeat units (or mer)

what does n stand for

degree of polymerization

morphology definition

the study of structure or form

crystalline regions

alignment and close packing of chainsn

on-crystalline regions (amorphous)

random arrangement of chains

semicrystalline

most polymers are semicrystalline

orientation in polymer morphology

refers to alignment of polymer chains in a particular direction

higher strength in orientation

high oriented

higher stiffness in orientation

highly oriented

examples of cellulosic fibers

lyocell, tencel, rayon, acetate, and triacetate

two definitions of spinning

1) "staple" or short (1/2'' to 2'') fibers are combined to form a yarn
2) "polymer" is converted into fibers or continuous "filaments"

what is denier?

the weight in grams of a length of 9000m

what is tex?

the weight in grams of 1000m of yarn

what is decitex?

the weight in grams of 10,000m

what does a larger denier, tex, or dtex mean?

the larger the denier (den), tex, or dtex, the heavier or thicker the yarn

what are bicomponent fibers?

two (bi-) polymers are extruded through different parts of the same spinneret to form one fiber

definition of filament count

the number of individuals fibers in a bundle

what is a monofilament?

a single strand of continuous fiber

what is a multifilament?

multiple strands of continuous fiber

how can stretch be produced?

stretch can be produced by using stretchy materials or texturing process

natural fiber identification

can be positively identified due to characteristic x-sectional and surface features

synthetic fiber identification

nearly impossible to identify under a microscope

yarn definition

a long thin continuous strand of fibers

indirect yarn numbering (Ne, Nw, Nm)

units of length per unit weight

Ne

english cotton countN

Nw

worsted count

Nm

worsted count

what unit of measurement is Ne?

numbers of Hanks (840 yds) per pound of yarn

what is the unit of measurement for Nw?

number of 560yd lengths in 1 pound

what type of fabric is Nw used for?

wool

what is the unit of measurement for Nm?

number of 1km lengths in 1kg

woven fabric definition

fabrics produced from 2 sets of yarns interlaced at 90° to each other

knitted fabric definition

fabrics formed by the interlacement of loops

interlacement of loops across fabric width

weft knits

interlacement of loops along the fabric length

warp knits

non-woven definition

fabric structures made directly from polymers/fibers

plain weave characteristics

most common, yarns change position at every crossover point, repeats on (2 ends and 2 picks), forms a flat fabric with an identical face and backc

twill weave

distinct diagonal lines seen going from left to right or right to left

classifications for twill weave

right hand twill, left hand twill, warp faced twill, unbalanced twill, balanced twill

right and left hand twill

the direction of the diagonal determines whether it is a left or right hand twill

left-hand twill

the diagonal moves from lower right to upper left

right-hand twill

the diagonal moves from lower left to upper rightw

warp faced twill

twill fabrics in which more of the warp yarn is seen on the face

filling faced twill

twill fabrics in which more of the filling yarn is seen on the face

balanced twill

the warp yarn goes over and under the same number of yarnsu

unbalanced twill

the warp yarn goes over and under a different number of yarns

satin weave

satin weave fabrics are warp faced (have long floats in the warp direction)w

what type of fabrics are satin weaves used for?

formal fabrics

what type of applications are sateen weaves used for?

tend to be used in less formal applications, drapery products and upholstery

sateen weave fabrics

are filling faced (have long floats in the filling direction)

basket weave

yarns in both directions weave in groups
(2 over, 2 under ; 3 over, 3 under ; etc.

warp rib

appear across the width of the fabric
multiple (or thick) filling yarn
epi > ppi

filling rib

appear along the length of the fabric
multiple (or thick) warp yarns are used
ppi > epi

definition of fabric weight

weight per unit area of fabrics

EPI

ends per inch
- number of ends in one inch (along the width) of a fabric

PPI

picks per inch
- number of picks in one inch (along the length) of a fabric

fabric count

EPI x PPI

balanced weave

EPI = PPI

cover

area (actually) covered by a woven fabric
- holes (interstices) do not count
- higher cover implies less light transmission and more opacity

cam weave

can manipulate fewest groups (2-8 harnesses)

dobby weave

can manipulate more groups (8-28)

jacquard weave

no limits, can control individual warp yarns

specialty fabrics

leno, pile, double, and crepe

leno fabrics

warp yarns cross one another along fabric length

leno open structure examples

mosquito netting, carpet backing

leno weight

light (translucent)
heavy (opaque)

pile fabric

weaving process creates cut or uncut loops on one or both sides of the base fabric

cut pile fabric

fabrics in which the loops are cut

uncut pile fabric

fabrics in which the loops are not cut

double cloth fabric

two layers of a fabric in a unitary structure
- can be more than two layers

how are double cloth fabrics held together?

held together by the rans in the fabric itself

crepe fabric

fabrics with long floats and high twist yarns producing a crinkly or pebbly feel and appearance

what is a true crepe?

a crepe with a plain weave and high twist warp yarns

crepe applications?

dress and blouse fabrics, table linens

hybrid fabrics

have layer(s) of fabrics combined with films (laminated or coated), yarns, or fibers

tufted hybrid fabric

fabrics that have a pile consisting of loops or tufts

tufted fabric applications

tufted carpets and upholstery

flocked hybrid fabrics

fabrics composed of very short fibers standing vertically on the surface on one or both sides of a base fabric

flocked fabric process

- an adhesive coated base fabric passes through a high voltage electrostatic field
- the flock fibers are electrically charged
- the charged fibers are attracted to the grounded electrode
- the flock moves towards the adhesive coated substrate and becomes embedded

flock fabric applications

clothing, upholstery, drapery, bedspreads, jewelry, stuffed toys, air filtration materials

what is ultrasuede?

foam and fiber fabric

coated fabrics

polymer (often elastomer), usually in viscous form, is applied directly on the fabric

coated fabric process

spreading a "thick" polymer solution or dispersion onto a fabric to form a continuous layer