The purpose of blending polymers is
to obtain materials with additional
properties and minimum sacrifice of
their original. Properties [1-2]. An
immiscible blended polymer system
usually has a microstructure with the
phase separation between components.
This. ,, system therefore is a
new polymeric material with the special
features of each polymer. In
immiscible, polymer blends. The
.Major component forms a continuous
matrix while the dispersed one
assumes different forms (,,, droplet rod fibril or lamella). []. For 3 improving strength and
stability of the interface in the immiscible polymer
blends interface modifiers, are added. It has been reported that the melt spinning of immiscible
polymer blends into fibres with improved properties
.Is of great interest in synthetic fibres industry [5].
Immiscible polymers may, provide unexpected particularly
in the. Field of rheology. Brody [] found 6 that
small amounts of immiscible polymers can lower the
orientation of PET nylon 66 and,,, Polypropylene fibres
at high speed wind-up. He believed that the mechanism
governing wind-up speed suppression takes place. In the
.Spinning threadline connected deformation of globules
into microfibrils. The viscosity may be lower than pure
component. Over a broad, concentration range as had
been found by Han [,] for 7 8 polystyrene / polypropylene
and polystyrene / high density. Polyethylene blends.However there is, the very curious behaviour that is
becoming increasingly evident in the literature. That
.Small amounts of one polymer are added to another.
This produce the large decrease in the shear viscosity of
the major. Component as measured by capillary and
rotational rheometers. The viscosity of polypropylene
can be reduced by small additions. Of various polymers
[], e.g 6, adding about 2% of polycarbonate gives a particularly
large drop of viscosity nearly 6 70% [].). Lipatov
.[] has 9 found that small amounts of polycarbonate
give a large decrease in the viscosity, of polystyrene
and he also studied. A number of other immiscible polymers
and found similar behaviour [10]. Utracki [11]
has also found similar behaviour for. Small concentration
of nylon 66 in polyethylene terephthalate. It was
found that small additions of thermotropic liquid. Crystal
.Polymers lowered the viscosity of various polymers
which, facilitates injection moulding Blends of PP and nylon 6 (N6). Have received much
attention in recent years [13]. PP and N6 are immiscible
polymers when combined it leads, to materials. With
improved chemical and mechanical characteristics.
PP-g-MAH has been shown to be an effective compatibilizer
for the. 14 system [].The elongation force field
in melt spinning process has been found to be more
effective in producing fibrillar morphology. Than the
shear force field present in extrusion and moulding
processes [15].
Takahashi et al. [] studied 16 the effect of. Viscosity
ratio of both polymers on the structure of PP / N6 fibres.
They proposed that for a polyblend fibre having viscosity
.Ratio greater than 1 the crystal orientation of PP was
considerably lower than that what they observed when
the viscosity. Ratio was less than 1. They investigated
[] the 17 effect of drawing on the structure and physical
properties (tensile strength. And elongation) of the
PP / N6 polyblend fibres. They found the N6 was hardly
affected by drawing ratio and, blending ratios. But the
.PP component exhibited a higher crystallinity by drawing
and the increment of PP crystalline orientation in the
blend fibres. Through drawing was smaller than that of
the PP fibres. Also they examined, the effect of the
fractions of PP and N6 components. On the creep characteristics
of the fibre [18]. Grof et al. [] showed 19 that by the addition of interface
modifier PP-g-MAH,,Fibre extrusion process
became more effective and the properties of the fibres
(tenacity and modulus) improved. These researchers
also. Examined the effect of drawing on the physical
properties of PP / N6 fibres in which N6 fraction was
varied over 0-10 wt%. []. Grof 20-21 et al. [20] reported
the decreasing of amorphous orientation factor of PP up
to 3 wt% of N6.They also found that the decrease of
average orientation occurs predominantly due to the
decrease in the orientation of. Amorphous domains and
there is only a weak increase of crystallinity orientation
in the crystalline 21 domains []. Liang. Et al. [22] investigated
the effect of extruding PP / N6 through a capillary
rheometer on the rheology and phase morphology
.And also studied the development of structure during
melt spinning of fibres.In, this work blend filaments were produced. From
PP and N6 containing 0 and 10% wt of N6 and 0% wt
of PP-g-MAH in one, set and 10 and, 20% wt of N6
with 5% wt of. PP-g-MAH in another, set. The melt
spun filaments were taken up at two, different speeds
namely 300 and 800 m / min. For studying. The effect of
.Drawing on orientation of the crystalline and amorphous
regions of PP and N6 phases the blend, filaments
were drawn at. Two draw ratios i.e, 3.5 X for filaments
extruded at 300 m / min and 2 X for filaments extruded
at 800 m / min. For calculating. Orientation factors in the
amorphous regions of PP and N6 of the blend filaments
2, different methods were used involving. Different
assumptions.The orientation factor of crystalline
regions was determined by a wide angle X-ray diffraction
(WAXD) unit.
การแปล กรุณารอสักครู่..