CTD 261 EXAM 2 QUESTIONS AND ANSWERS 100% CORRECTCTD 261 EXAM 2 QUESTIONS AND ANSWERS 100% CORRECTCTD 261 EXAM 2 QUESTIONS AND ANSWERS 100% CORRECTManufactured Fiber Differences - ANSWER-Appearance and hand are not enough
Chemistry is where there is a difference
Generic names are used
Direct end...
CTD 261 EXAM 2 QUESTIONS AND
ANSWERS 100% CORRECT
Manufactured Fiber Differences - ANSWER-Appearance and hand are not enough
Chemistry is where there is a difference
Generic names are used
Direct end-uses of fibers and fashions
Spandex
Fiber Manufacturing - ANSWER--Converting material into fiber form is called "spinning"
-Starting material is a polymer, either supplied by nature, or manufactured from
petrochemicals
-Polymer is made into a viscous fluid, either by application of heat (melting), or by use of
a solvent for the material (dissolving)
-The spinning solution is referred to as dope.
Spinning Steps - ANSWER-1) Melting/Dissolving, preparing solution
2) Extrusion- through spinneret to form fiber
3) Hardening: Cooling/Evaporation/Precipitation
-Drawing
-Orientation and crystallinity
-Fiber diameter
Methods of Manufacturing Fibers - ANSWER-1) Melt Spinning: Molten polymer is forced
through the spinneret into air; fiber forms by freezing (cooling).
2) Drying Spinning: Polymer solution is forced through the spinneret into warm air or
nitrogen; fiber forms by evaporation of solvent
3) Wet Spinning: Polymer solution is forced through the spinneret into a bath of
nonsolvent; fiber forms by precipitation or coagulation
Spinning - ANSWER-Melt Spinning requires high temperatures but is cleaner, and is the
preferred process. Some polymers break down before they melt, and so must be spun
from solution. In wet or dry spinning, solvent must be recovered
Spinneret Modifications
Fiber Size - ANSWER--Fiber Size: Control size of spinneret opening, amount of
drawing, or extrusion rate; side based on end use
-Apparel: less than 7 denier
-Furnishings: 5-25 denier
-Industrial: any size
-Microdenier: less than 1.0 denier per filament (dpf)
-Ultrafine fibers: Smaller than microdenier fibers
-Mixed denier fiber building: Combines regular size fiber with microfibers in a yarn
, Spinneret Modifications
Fiber Shape - ANSWER--Fiber Shape: Alter properties
-Solid fibers: Even diameter
-Thick-thin fibers: Uneven diameter
-Hollow/multicellular fibers: Use gas-forming compounds, inject air, or modify spinneret
hole
-Trilobal shape: Three-sided fiber cross sectional shape designed to imitate silk
Molecular Structure and Crystallinity Modifications - ANSWER--High tenacity fiber types
-Draw or stretch to increase orientation
-Chemical modifications increase DoP
-Low-pilling: Decrease molecular weight slightly to reduce flex life and decrease pilling
-Binder staple: Polyester with very low melting point. It bonds with other fibers when
exposed to heat above its melting point
-Low-elongation modifications: Reinforcing fibers to blend with cellulosic fibers
Fiber Cross-Section - ANSWER--The cross section of a natural fiber is whatever nature
provides; little can be done to change it. ---
-One exception to this rule is that the cross-section of cotton can be changed from a
"flattened lima bean" shape to nearly circular by mercerizing the textile yarn of fabric
under tension
-The cross section of a manufactured fiber depends upon the spinning process, and in
some cases, particularly in melt spinning, can be controlled by the shape of the
spinneret holes.
Matrix-Fibril - ANSWER-One polymer forms a continuous phase with the other within it
in the form of very small fibers called fibrils. Used for specialty fabric production. A way
to produce microfibers.
Delustering-titanium dioxide - ANSWER-dded in spinning solution, breaks up light so
fiber not as shiny
Whiteners or brighteners - ANSWER-resist yellowing
Cross dyeable or dye affinity - ANSWER-Dye-accepting chemicals incorporated into
molecular structure as a direct part of polymer; not colored when extruded
Wet spun - ANSWER-Irregular cross section due to evaporation of solvent: rayon
Dry Spun - ANSWER-Irregular, collapsed due to evaporation of solvent: acetate
Melt spun - ANSWER-Round, specific shape determined by spinneret hole
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