Polymer Blends Handbook

1191 Pages·2003·13 MB·English

by  L. A. Utracki (auth.), L. A. Utracki (eds.)

CHAPTER 1
INTRODUCTION TO POLYMER BLENDS
L. A. Utracki
National Research Council Canada, Industrial Materials Institute,
Boucherville, QC, Canada
An Introductory Note
In this introductory chapter the basic information on polymer blends (with a special
emphasis on the commercial alloys) is presented in the sequence: (i) a historical
perspective on the polymer science and technology, (ii) polymeric structures and
nomenclature, (iii) fundamental concepts in polymer blend science, and (iv) evolution
of polymer blends’ technology.
The world production of plastics in 1900 was about 30,000 tons — in the year 2000
it is expected to reach 151 Mt. The projected saturation level on the global scale (an
increase by a factor of ten) is expected to be reached in the middle of the 21st century.
The rapidity of the plastics expansion can be best judged by comparing it with steel —
already in 1992 the annual world production of plastics more than doubled in volume
the world production of steel, and nearly tripled its value. Polymers are the fastest
growing structural materials. It is noteworthy that the polymer blend segment of the
plastics industry increases at a rate about three times higher than the whole.
Polymers are classifi ed as either natural that resulted from natural biosynthesis,
or synthetic. The natural (polysaccharides, proteins, nucleic acids, natural rubbers,
cellulose, lignin, etc.) have been used for tens of thousands of years. In Egypt the
musical string instruments, papyrus for writing, and styrene [in a tree balsam] for
embalming were used 3,000 BC. For millennia shellac has been used in Indian turnery
[Chattopadhyaya, 1986]. The natural rubber was used by Olmecs at least 3000 years
ago [Stuart, 1993].
The term synthetic polymer refers equally well to linear, saturated macromolecules
(i.e., thermoplastics), to unsaturated polymers (i.e., rubbers), or to any substance based
on crosslinkable monomers, macromers, or pre-polymers (i.e., thermosets). The focus
of this handbook is on blends of thermoplastics made of predominantly saturated,
linear macromolecules.
There are many sources of information about polymer history [Martuscelli et al.,
1987; Seymour and Cheng, 1987; Vogl and Immergut, 1987; Alper and Nelson, 1989;
Morris, 1989; Seymour, 1989; Sperling, 1992; Mark, 1993; Sparke, 1993; Utracki,
1994, 1998a]. The abbreviations used in this text are listed in Appendix 1. International
Abbreviations for polymers and polymer processing.
L.A. Utracki (Ed.), Polymer Blends Handbook, 1-122.
© 2003 Kluwer Academic Publishers. Printed in the Netherlands.
2 L. A. Utracki
1.1 Early Polymer Industry commercialized in 1930 as Thiokol™. In 1937
butyl rubber (copolymer of isobutylene with
1.1.1 The Beginnings isoprene) was invented. The synthetic rubber
production took a big leap during the second
The polymer industry traces its beginning to the world war (WW-2) [Morton, 1982].
early modifi cations of shellac, natural rubber (NR —
an amorphous cis-1,4-polyisoprene), gutta-percha 1.1.4 Synthetic Thermosetting Polymers
(GP — a semi-crystalline trans-1,4-polyisoprene),
and cellulose. In 1846, Parkes patented the fi rst The fi rst commercially successful synthetic polymer
polymer blend: NR with GP partially co-dissolved was phenol-formaldehyde (PF) [Smith, 1899].
in CS . Blending these two isomers resulted in The resin was introduced in 1909 by Baekeland as
2
partially crosslinked (co-vulcanized) materials Bakelite™. The urea-formaldehyde resins (UF),
whose rigidity was controllable by composition. were discovered in 1884, but production of Beetle™
The blends had many applications ranging from moldable resin commenced in 1928. Three years
picture frames, table-ware, ear-trumpets, to sheath- later, Formica™, phenolic paper covered with
ing the fi rst submarine cables. decorative layer protected by UF, was introduced.
The thiourea-formaldehyde molding powders
1.1.2 Modifi ed Natural Polymers were commercialized in 1920, while in 1935,
Ciba introduced Cibanite™, aniline-formaldehyde
The fi rst man-made polymer was nitrocellulose (AF) molding materials, then two years later, the
(NC). The main use of the NC resins was a melamine-formaldehyde (MF).
replacement of the natural and expensive materials, Epoxy compounds were discovered by Prileschaiev
viz., ivory, tortoise shell products, amber, ebony, in 1909, but its importance was realized only
onyx or alabaster. The use of cellulose acetate during WW-2. In 1956, glass fi ber reinforcements
(CA) as a thermoplastic began in 1926. Cellulose were introduced. The thermoset polyesters (TS)
ethers and esters became commercially available were developed by Ellis in 1933-4. The fi rst use
in 1927. Casein crosslinked by formaldehyde of glass-reinforced TS dates from 1938.
gave horn-like materials — Galalith™ has been
used to manufacture shirt buttons, or as imitation 1.1.5 Synthetic Thermoplastic Polymers
of ivory and porcelain [Pontio, 1919].
The synthetic polymers are divided into three
1.1.3 Synthetic Rubbers categories:
1. Commodity,
The fi rst polymerization of isoprene in sealed 2. Engineering, and
bottles was reported in 1884 by Tilden. Methyl 3. Specialty.
rubber was thermally polymerized at 70°C —
the reaction required 3 to 6 months, giving The fi ve large-volume polymeric families that
poor quality products. In 1926 BASF developed belong to the Commodity resins are: polyethyl-
sodium-initiated polymerization of butadiene enes (PE), polypropylenes (PP), styrenics (PS),
known as Buna™ (for BUtadiene + Natrium). acrylics (PMMA), and vinyls (PVC). Their world
The fi rst successful, general purpose rubbers market share (see Table 1.1) remains relatively
were copolymers of butadiene with either styrene, stable — they represent 79% of all plastics.
Buna-S, or acrylonitrile, Buna-N [Tschunkur The fi ve engineering polymer families are:
and Bock, 1933; Konrad and Tschunkur, 1934]. polyamides (PA), thermoplastic polyesters (PEST),
Poly(2-chlorobutadiene), chloroprene [Carothers polycarbonates (PC), polyoxymethylenes (POM),
et al., 1931], was introduced in 1931 by DuPont. and polyphenylene ethers (PPE). They constitute
Elastomeric polysulfi des [Patrick, 1932] were about 11% by volume and 34% by value of
Introduction to Polymer Blends 3
Table 1.1. World Market Share (MS) and Annual Growth Rate (AGR) by Resin Type (1995-2000)
No. Resin Type MS (%) AGR (%)
1. Low density polyethylene (LDPE + LLDPE) 20 5.1
2. High density polyethylene (HDPE) 13 5.2
3. Polypropylene (PP) 17 6.6
4. Polystyrene and copolymers (PS + ABS) 11 4.7
5. Polyvinylchloride (PVC) 18 5.2
6. Other thermoplastics (TP) 11 4.5
7. Thermosets (TS) 10 -2.1
the plastic’s consumption. The engineering New types of polymers are also being intro-
and specialty polymers show high mechanical duced, e.g., dendritic-structure polymers [Fréchet
performance, and the continuous use temperature et al., 1992], carbosilane dendritic macromolecules
150 ” CUT(°C) ” 500. [Roovers et al., 1993], the “hairy rod” molecular
The polymer industry increasingly favors structures where rigid-rod chain macromolecules
high technology and high value-added materials. are provided with short and fl exible side branches
These are obtained either by means of new polym- [Wegner, 1992], etc. However, the polymer tech-
erization methods, new processing technologies, nology invariably moves away from the single
or by alloying and reinforcing. For example, new phase materials to diverse combinations of polymers,
syndiotactic PP or PS (sPP or sPS, respectively) additives, and reinforcements. While synergistic
surpasses the performance of their predecessors. effects are often cited, the main reason is a
The gel spun PE fi bers have 200 times higher need for widening the range of properties, for
tensile strength than standard PE. New aromatic development of materials that would have the
polyester (EKF from Sumitomo) has tensile strength desired combination of properties — tailor-made
of 4.1 GPa, to be compared with 70 MPa of a polymeric systems. At present, about 36% of
standard polyester resin (see Table 1.2). the synthetic resins are used in blends and about
39% in composites.
Table 1.2. High performance materials — a comparison
No. Material Strength (GPa) Modulus (GPa)
Theoretical Observed Theoretical Observed
1. Polyethylene (standard) 21 ” 0.03 316 0.2
2. Polyethylene gel-spun 21 6.0 316 220
3. Polyester (standard) 24 0.07 124 2.2
4. Polyester oriented 24 1.2 124 21
5. Aromatic Polyamide 21 3.6 190 125
6. Aromatic Polyester (EFK) - 4.1 - 139
7. Poly(phenylene benzothiazole) - 4.2 371 365
8. Polyazomethin - 4.7 - 125
9. Carbon fi ber - 3.1 - 235
10. Steel 29 2.1 to 3.5 - 210
4 L. A. Utracki
1.1.6 Compounding and Processing mining the reaction progress and morphology
[Nishio et al., 1990]. American Leistritz has been
The fi rst mixer was an annular container with a active in designing TSE kneading elements that
spiked rotor for rubber compounding [Hancock, improved mixing capability by maximizing the
1823]. The calender/two roll mill was patented by extensional fl ow fi eld. More information on the
Chaffe in 1836 and manufactured by Farrel Co. evolution of the extrusion technology can be
A counter rotating twin shaft internal mixer with found in Chapter 9. Compounding Polymer Blends.
elliptical rotating discs or sigma-blades was devel- Injection molding of NC dates from 1872.
oped by the end of the last century [Freyburger, The early machines were hand operated. They used
1876; Pfl eiderer, 1880]. The fi rst hand-operated an axially movable screw or plunger and were
extruder was a ram press, used for forming NR equipped for devolatilization. The commercial-
or GP, then later NC. scale injection molding of PS has begun in 1931.
The fi rst, belt-driven extruders with Archimedean In 1932 Gastrow developed the fi rst automatic unit,
screw were patented nearly a century later [Gray, Isoma-Automat (30 g capacity per shot), with torpe-
1879]. In 1939, Paul Leistritz Maschinenfabrik built do-type heating chamber. In 1951, Willert invented
electrically heated, air cooled extruder, with nitrited an in-line reciprocating screw plasticization that
barrel, having L/D = 10, an automatic temperature revolutionized the injection molding industry.
control, variable screw speed. The machine is The fi rst automated injection molding plant was
considered a precursor of the modern single-screw developed by Eastman Kodak in 1950.
extruders, SSE. During the WW-2 breaker plates, Hayatt used blow molding in 1880 to produce
screen packs, crosshead dies, coextrusion, monofi la- baby rattles out of CA tubes or sheets. In 1942,
ment extrusion, fi lm blowing and biaxial sheet Plax Corp. started manufacturing squeezable
orientation were introduced. In the 1950’s, a coex- LDPE bottles. By the end of 1950’s blow molding
trusion process, venting, and two-stage screws were was the most rapidly developing processing method.
developed. In 1980’s the microprocessor control In 1965 Wyeth, using the stretch blow molding,
evolved into computer integrated manufacturing, produced PET bottles. In 1972, Toyo Seikan started
the helical grooved feed barrels, high pressure gear to produce multilayered blow molded bottles
pumps, air lubricated die fl ow, biaxial fi lm orienta- from PP and EVAl. In 1976 Ishikawajima-Harima
tion were introduced [Utracki, 1991a, c]. introduced intermittent coextrusion blow-molding
Pfl eiderer patented the fi rst modular coun- system for large parts.
ter-rotating twin-screw extruder (TSE) in 1882.
An intermeshing, corotating TSE, the predecessor 1.1.7 Development of Polymer Science
of the modern machines, was designed for extrusion
of CA. The TSE was used by I. G. Farbenindustrie 1.1.7.1 Polymerization
for the production of PA-6 [Colombo, 1939].
In 1959, Werner & Pfl eiderer introduced ZSK Cellulose modifi cation dates from 1833 (Braconnot).
machines (vented, intermeshing, corotating, with In 1838 Regnault photo-polymerized vinylidene
segmented screw and barrel, twin-screw extruders). chloride. A year later Simon observed that heating
These provided good balance between the disper- styrene in the presence of air generated a tough
sive and distributive mixing at relatively high gelatinous material — a low molecular weight PS.
output rates. In 1979 Japan Steel Works (JSW) Polyoxymethylene (acetal) was discovered in 1859.
developed TEX-series TSE’s for reactive com- In 1872 several new polymers were announced,
pounding, permitting an easy change of the screw viz., PVC, polyvinyl bromide (PVB) and phenol-
direction from co- to counter-rotation. In col- formaldehyde (PF). Polymethacrylates were dis-
laboration with Sumitomo Chem., barrel elements covered by Kahlbaum in 1880, polymethylene
with sampling ports were designed, providing in 1897, one year later polycarbonate (PC) by
ready access to the processed material for deter- Einhorn, polyamide-6 (PA-6) in 1907, etc. In the
Introduction to Polymer Blends 5
1920’s the list of polymers rapidly started to (2), where (1) is halide or oxyhalide of transition
increase, viz. polysulfi de (PSF), polyvinyl alcohol metals from groups IV to VII, and (2) is an
(PVAl), poly(styrene-co-maleic anhydride) (SMA), organometallic compound of metal from groups
polyvinylformal (PVFO). During the next decade I to III. The Z-N-catalyst are prepared by mixing
polyacetylene (PACE), styrene-acrylonitrile copo- ingredients (1) and (2) in a dry, oxygen-free
lymer (SAN), low density polyethylene (LDPE), solvent [Natta and Danusso, 1967]. Recently
polyvinylidenechloride (PVDC), epoxy resins Z-N catalysis is in renaissance, with new MgCl -
2
(EP), polyamides (e.g., PA-66; PA-610; PA-106), supported catalysts that have a hundred-fold more
polysiloxanes (PDMS), polychlorotrifl uoroethylene active sites per mole of Ti and about ten times
(PCTF), polytetrafl uoroethylene (PTFE), and many higher propagation rate [Rieger et al., 1990].
others, were discovered [Utracki, 1989a]. The new, single-site metallocene catalysts
Most early thermoplastics, e.g., PVC or PS, make it possible to control MW, molecular weight
were obtained in the free radical polymerization, distribution (MWD), comonomer placement,
initiated either by heat or by sunlight. The fi rst stereoregularity, and life-time of the reactive
systematic studies of the free radical chemistry chain-end [Kaminsky et al., 1985, 1992; Kaminsky,
commenced 80 years later [Ostromislensky, 1911, 1998; Swogger, 1998]. The use of either
1915, 1916]. Fikentscher empirically determined (Cp) R’ (Cp)MeQ , or R” (Cp) MeQ’ {where:
p s 3-p s 2
which one of the 30-or-so monomers liked or disliked Cp is cyclopentadienyl (substituted or not) radical,
to copolymerize with each other. The advantage Me is metal from Group 4b, 5b, or 6b, R’, R”,
of latex-blending was also established. The theory Q and Q’ are radicals (viz. aryl, alkyl, alkenyl,
of the free radical copolymerization was fi nally alkylaryl, or arylalkyl), s = 0-1, p = 0-2}, for
developed in the 1940’s [Alfrey et al., 1952]. the polymerization of ethylene copolymers, pro-
The polycondensation reactions have been vides independent control of MW and density.
known since the mid-1800 [Lourenço, 1859; The catalyst is used in combination with a large
Wurtz, 1859, 1860]. In 1927, Carothers and his amount of alumoxanes.
colleagues provided the basis for understanding the In 1975 Mitsui Petrochemicals introduced metal-
nature of these reactions. Good agreement between locene-made LLDPE Tafmer™, with controlled
Flory’s theoretical predictions and the experimental comonomer placement, but rather low MW. In 1991,
observations of the average molecular weight (MW) Dow Plastics produced developmental quantities
provided convincing arguments for the acceptance of ethylene copolymers with up to 25 mole %
of the linear macromolecule model. of butene, hexene or octene, Affi nity™ resins.
The alkyl-lithium initiated, living anionic The use of a metallocene catalyst with a single
polymerization of elastomers was described in cyclopentadiene ring, resulted in a certain degree
1928 by Ziegler. To polymerize styrene-isoprene of randomization of the polymerization process.
block copolymers Szwarc et al., [1956] used sodi- The catalyst produced PP with narrow molecular
um naphthalene as an anion-radical di-initiator, weight distribution, and a long chain branching,
while Shell used an organolithium initiator. similar to LDPE.
The polymerization mechanism was described The metallocene catalysts are also used to
by Bywater [1965]. produce high melting point polymers out of com-
In the early 1950’s, Ziegler found that in modity monomers, e.g., sPS, with T = 100°C, and
g
the presence of ZrCl + AlR ethylene can be T = 266°C, or syndiotactic poly(p-phenyl styrene),
4 3 m
polymerized at low temperature and pressure (sPhPS), with T = 196°C, T = 352°C, and
g m
into linear, high density polyethylene (HDPE). the decomposition temperature, T = 380°C.
decomp
The catalysts developed by Ziegler, and later by Since sPhPS is miscible with sPS in the whole
Natta become known as Ziegler-Natta, or Z-N range of concentration, blends of these two
catalysts. These can be defi ned as polymerization syndiotactic polymers can be processed at any
initiators created from a catalyst (1) and co-catalyst temperature above 266°C [Watanabe et al., 1992].
6 L. A. Utracki
Polycyclohexylethylene (PCHE) is a new is immeasurably high, η → ∞. Good correlation
metallocene resin, developed by Dow as a replace- was found between V and either the critical
occ
ment for PC in the production of optical discs. volume or the van der Waals constant b, viz.
PCHE has low shrinkage (0.02% after 24 hrs), V / (V / 3) = V / b = 0.921 ± 0.018.
occ crit occ
higher light transmission than PC (91.9% vs. 89.8%, Batschinski wrote:
respectively) and high fl ex modulus of 71 GPa.
Commercial production is to start by the year 2000. η = a + a / f = a + a V / (V - V ) (1.2)
0 1 0 1 occ
In 1999 Equistar Chem. Introduced high per-
formance, non-metallocene single-site catalyst where a are equation parameters. Forty years
i
for PE’s. later, more accurate data of viscosity (spanning
several orders of magnitude) and specifi c volume
1.1.7.2 Polymer Physics for a series of paraffi n’s with molecular weight
MW = 72 to 1000 g/mol led to the logarithmic
Molecular Weight (MW) dependence [Doolittle, 1951]:
Osmotic pressure measurements for the determi-
nation of MW were used in 1900 to characterize ln η = a + a V / (V - V ) (1.3)
0 1 o o
starch. Twenty years later, the solution viscosity
measurements were introduced by Staudinger for where V is the value of V at a characteristic solidi-
o
this purpose. However, it was Mark and his fi cation temperature, T , at which the fl uid viscosity
o
collaborators who developed the concept of the increases to infi nity. Eq 1.3 provided a basis for the
intrinsic viscosity ([η]) and demonstrated that it derivation of well-known WLF time-temperature
provides information on the volume of individual shift factor a [Williams et al., 1955].
T
colloidal particles, thus on MW. For the freely The free volume model has been also incorpo-
rotating chains the dependence (today known as rated into thermodynamic theories of liquids and
Mark-Houwink-Sakurada equation) was obtained solutions [Prigogine et al., 1957] and it is an
[Guth and Mark, 1934]: integral part of theories used for the interpretation
of thermodynamic properties of polymer blends
a

[η] ≡ lim [(η/η ) - 1] / c = KM (1.1) [Utracki, 1989a]. In particular, it is a part of the
Ο v
c → 0
most successful equation of state (EoS) derived
where η and η are viscosities of the solution and for liquids and glasses [Simha and Somcynsky,
ο
solvent, M is the viscosity-average molecular 1969], critically examined using data for 56
v
weight, and K and a = 0.5-0.7, are equation param- principal polymers [Rodgers, 1993]. Since the
eters. In 1933 the ultra-centrifugation was intro- mid-1960’s, the lifetime of ortho-positronium
duced [Kraemer and Lansing, 1933]. Utility of light has been used to measure the free volume
scattering for the determination of MW was demon- fraction f. Accordingly, f increases linearly with
strated eleven years later [Debye, 1944, 1946]. the temperature: f = -0.13556 + 6.2878(T/T*)
for 0.0165 ” T/T* ” 0.0703, where T* is the tem-
Free Volume Concept perature reducing parameter in Simha-Somcynsky
The free volume theory of liquids dates from the theory [Utracki, 1998b]. More detailed analysis
beginning of the 20th century. Two expressions indicated that the free volume should be dis-
for the free volume fraction, f, have been proposed, cussed in terms of distribution of the holes.
either f = (V - V )/V or less frequently used For example, the measurements showed that
occ
f = (V - V )/V , (V is the occupied volume). above T the number of holes does not increase,
D occ occ occ g
The theory was used to interpret the temperature (T) but their volume does [Kobayashi et al., 1989].
and pressure (P) dependencies of liquid viscosity In PS/PPE blends, the size of the free volume
[Batschinski, 1913]. The V was defi ned as the spaces in PS was found smaller than that in PPE
occ
specifi c volume at which the liquid viscosity [Li et al., 1999].
Introduction to Polymer Blends 7
Viscoelasticity are in good agreement with the observations: η
o
3.4
In 1874, Boltzmann formulated the theory of vis- ∝ M . The correlation between the plateau modu-
coelasticity, giving the foundation to the modern lus and entanglement concentration soon followed
rheology. The concept of the relaxation spectrum [Ferry et al., 1955]. The long disputes on the nature
was introduced by Thompson in 1888. The spring- of entanglement led to defi ning it as “a special
and-dashpot analogy of the viscoelastic behavior type of interactions, affecting mainly the large-
(Maxwell and Voigt models) appeared in 1906. scale motions of the chains, and through them, the
The statistical approach to polymer problems was long time end of the viscoelastic relaxation time
introduced by Kuhn [1930]. spectrum” [Graessley, 1974].
Busse [1932] observed that “green” rubber
under stress shows a dual behavior, suggesting
presence of two types of interactions: few widely 1.2 Polymer Structure and Nomenclature
separated strong ones, acting as physical crosslinks,
and many weak ones of the van der Waals type, 1.2.1 Basic Considerations
that make it possible for one macromolecule to
slip by the others. This postulate was the fi rst Polymer is a substance composed of macro-
connotation of the chain entanglement. Bueche molecules, built by covalently joining at least 50
[1952, 1956, 1962] adopted the entanglements’ molecular mers, or the Constitutional Repeating
concept for the interpretation of polymer fl ow. Units or CRU. The longest sequence of CRU
He calculated the molecular friction constant defi nes the main chain of a macromolecule.
per statistical segment as the unit force needed The main chain may be composed of a series
to pull the undeformed macromolecule through of subchains, identifi ed by some chemical of
the surrounding medium at unit speed, f = F/N physical characteristic (e.g., tactic placement).
o
(with N being the number of statistical segments per The main chain may also contain long or short
macromolecule), deriving the relations (see Eq 1.4) side chains or branches, attached to it at the
between the diffusion constant, D, or zero-shear branch points. A small region in a macromolecule
viscosity, η , and such molecular parameters as from which at least four chains emanate consti-
ο
density, ρ, molecular weight, M, and radius of tutes a crosslinking point. A macromolecule that
gyration, R : has only one crosslink is the star macromolecule.
g
2 A macromolecule consisting of several cross-
D η o = ( ρ N A / 3 6 ) ( R g / M ) k B T ; (1.4)
linked chains, but having a fi nite molecular weight
and
is a micronetwork. A highly ramifi ed macro-
2
ηo = (ρNA / 36)(Rg / M)N * fo molecule in which each CRU is connected to every
other CRU is a polymer network. When the main
for: M ≤ 2Me N* = M / Mo
chain of a macromolecule has numerous branch
for: M > 2Me
2 2 3/ 2 points from which linear side chains emanate, it
N* = β(M / Mo )(ρNA / 48)(M / Me ) M (Rg / M)
is comb macromolecule. The CRU is defi ned as
a bivalent organic group, not necessarily identical
to the source from which the macromolecule was
where numerical constant β ≅ 0.6. The dependence prepared — it is the largest identifi able group
predicts that for low molecular weight liquids in the polymer dictated by the macromolecular
(M below the value of the critical molecular structure. To discuss the structure of polymer
weight for entanglement, M = 2M , where M is molecules, one may consider the chemical nature
c e e
the molecular weight between entanglements) η of CRU, type of the linkages, the global macro-
o
should be proportional to M, while for high molecu- molecular arrangement, and the topochemical
3.5
lar weight macromolecules (above M ) to M . character of the macromolecule, tacticity, etc.
c
Thus, predictions of the entanglement-based theory These are summarized in Table 1.3.
8 L. A. Utracki
1.2.2 Polymer Nomenclature 4. The source of the compounds (viz., synthetic,
natural, and derived products).
Macromolecular compounds can be classifi ed
according to: The Commission on Macromolecular Nomen-
1. The chemical structure of the repeating unit clature defi ned 52 terms related to polymer
(viz. polyamides, polyesters, polyolefi ns). structure, including polymer, constitutional units,
2. The structure (viz. linear, branched, ladder, or monomer, polymerization, regular polymer, tactic
crosslinked). polymer, block polymer, graft polymer, monomeric
3. The phenomenological behavior or technologi- unit, degree of polymerization, addition polymeriza-
cal use. tion, condensation polymerization, homopolymer,
Table 1.3. Macromolecular structures
No. Characteristic Examples
1. Recurring Constitutional Repeating Units, CRU
1.1. Structure Aliphatic, aromatic, heterocyclic, metallo-organic, ...
1.2. Joining similar CRU Homopolymers (linear, branched, dendritic, crosslinked, etc.)
1.3. Joining different CRU Copolymers, multipolymers, polyadducts, polycondensates, ...
1.4. Joining polymer segments Block copolymers, graft copolymers, ladder polymers, ...
2. The nature of bond between CRU e.g., ether, ester, amide, urethane, sulfi te, ...
3. Macromolecular structure Linear, branched, cross-linked, dendritic, ...
4. Topochemical characteristics of macromolecule
4.1. Geometrical isomers e.g., rubber and gutta-percha are poly(1,4-isoprene), cis- and trans-, respectively
4.2. Optical isomers Having optically active C*; e.g., polypeptides, polysaccharides, ...
4.3. Tacticity Isotactic, syndiotactic, and atactic
4.4. Helical structures Polypeptides, tactic polymers
4.5. Head-to-tail, head-to-head Example: PIB or PS
Table 1.4. Polymer nomenclature proposed by the IUPAC
N o. Title Reference
1. Report on Nomenclature Dealing with Steric Regularity in High Polymers Huggins et al., 1966
2. Basic Defi nitions of Terms Relating to Polymers IUPAC, 1974; 1996
3. Nomenclature of Regular Single-Strand Organic Polymers IUPAC, 1976
4. Stereochemical Defi nitions and Notations Relating to Polymers IUPAC, 1981
5. Note on the Terminology for Molar Masses in Polymer Science IUPAC, 1984
6. Nomenclature for Regular Single-Strand and Quasi-Single-Strand IUPAC, 1985a
Inorganic and Coordination Polymers
7. Source-Based Nomenclature for Copolymers IUPAC, 1985b
8. Use of Abbreviations for Names of Polymeric Substances IUPAC, 1987
9. Defi nitions of Terms Relating to Individual Macromolecules, IUPAC, 1989a
their Assemblies, and Dilute Polymer Solutions
1 0. Defi nitions of, Terms Relating to Crystalline Polymers IUPAC, 1989b
1 1. A Classifi cation of Linear Single-Strand Polymers IUPAC, 1989c
1 2. Compendium of Macromolecular Nomenclature Metanomski, 1991
1 3. Source-Based Nomenclature for Non-Linear Macromolecules and Macromolecular Assemblies Jenkins et al., 1993
Introduction to Polymer Blends 9
copolymer, bipolymer, terpolymer, copolymeriza- 1.2.2.1 Structure-based Nomenclature
tion [IUPAC, 1974]. The Commission remains the
leading nomenclature body in the polymer fi eld. For organic, regular, single-strand polymers the
Table 1.4 lists the pertinent sources for informa- structure-based system of naming polymers should
tion on the nomenclature of polymeric materials. be used. This nomenclature describes chemical
Since there are diffi culties in assigning system- structures rather than substances. Three steps are
atic and unique abbreviations to polymers, only to be followed in a sequence: 1. Identify the con-
a short list has the IUPAC’s offi cial sanction. stitutional repeating unit, CRU. 2. Orient the CRU.
An extensive list of internationally used abbrevia- 3. Name the CRU. The name of the polymer is
tions is provided in Appendix I. The IUPAC poly(CRU). The preferred CRU is one beginning
Macromolecular Nomenclature Commission has with the subunit of highest seniority. The order
published three sets of rules for naming polymers: of seniority is: heterocyclic rings, chains contain-
1. Traditional, trivial names are sanctioned by the ing heteroatoms, (in the descending order O, S,
historical use and approved by IUPAC as an Se, Te, N, P), carbocyclic rings, chains contain-
alternative (examples are listed in Table 1.5), ing only carbon. The seniority is expressed by
2. Structure-based nomenclature, and brackets and internal parentheses (see examples
3. Source based nomenclature proposed by the in Table 1.5).
Commission.
Table 1.5. Traditional and systematic names of polymers
No. Traditional name Systematic name
1. polyethylene poly(methylene)
2. polypropylene poly(propylene)
3. polyisobutylene poly(1,1-dimethyl ethylene)
4. polybutadiene poly(1-butenylene)
5. polyisoprene poly(1-methyl- 1-butenylene)
6. polystyrene poly(1-phenyl ethylene)
7. polyacrylonitrile poly(1-cyano ethylene)
8. polyvinyl alcohol poly(1-hydroxy ethylene)
9. polyvinylacetate poly(1-acetoxy ethylene)
10. polyvinylchloride poly(1-chloro ethylene)
11. polyvinylidenefl uoride poly(1,1-difl uoro ethylene)
12. polytetrafl uoroethylene poly(difl uoro methylene)
13. polyvinylbutyral poly[(2-propyl-1,3-dioxane-4,6-diyl) methylene]
14. polymethylacrylate poly[1-(methoxycarbonyl) ethylene]
15. polymethylmethacrylate poly[1-(methoxycarbonyl)-1-methyl ethylene]
16. polyformaldehyde poly(oxy methylene)
17. polyethylene oxide poly(oxy ethylene)
18. polyphenylene ether poly(oxy-1,4-phenylene)
19. Polyethyleneterephthalate poly(oxyethylene-oxyterephthaloyl]
20. poly-ε-caprolactam poly[imino(1-oxohexamethylene)]
21. polyamide-6,6 or polyhexamethyleneadipamide poly[imino(1,6-dioxohexa methylene) iminohexa methylene];
or poly(iminoadipoyliminohexa methylene)
10 L. A. Utracki
After the CRU and its orientation, reading left For example, name such as polyvinyl alcohol
to right, have been established, the CRU or its refers to a hypothetical source, since this polymer
constituent subunits are named. The name (the is obtained by hydrolysis of polyvinylacetate.
largest identifi able unit) includes description of In spite of defi ciencies, the source-based nomen-
the main chain and the substituents. The subunits clature is still entrenched in the literature. It is also
are named according to the rules for nomenclature the basis for naming and classifying copolymers
of organic chemistry. The name of the CRU (see Table 1.6).
is formed by citing, in order, the names of
the largest subunits within the CRU. More 1.2.3 Copolymers
complicated, regular single-strand polymers can
be represented as multiples of repeating units, When mers are not identical the polymerization
such as [ABC] . The name of the polymer is leads to a copolymer. For divalent mers a linear
n
poly(ABC), where (ABC) stands for the names copolymer is obtained, but when at least some
of A, B, and C, taken in the order of seniority. mers are able to join more than two units, the
An extension of the structure-based method to polymerization leads to branched or crosslinked
linear inorganic and/or coordination polymers copolymer. When the polymerization starts on
is limited by the general lack of a system for a polymer chain of different chemical character
naming bivalent radical. Few polymers with that the one that is subsequently forming, the
inorganic, covalently-bonded backbones have resulting structure is known as grafted copolymer.
trivial names [viz., poly(dimethylsiloxane) or Thus, the arrangement of the different types
poly(dichlorophosphazene)], some can be named of monomeric units must be specifi ed. Several
(as organic polymers) by using bivalent radicals; types of arrangements are shown in Table 1.6,
e.g., poly[oxy(dimethyl silylene)] or poly[nitrilo where A, B, and C represent different CRU.
(dichlorophosphoranylidyne)]. The systematic source-based nomenclature for
Structure-based nomenclature is also appli- copolymers involves identifi cation of the constitu-
cable to copolymers having a regular structure, ent monomers, and description of their arrange-
regardless of the starting materials used [viz. ment. This is achieved by citing the names of
poly(oxyethylene-oxyterephthaloyl)]. In princi- the constituent monomers after the prefi x “poly”,
ple, it should be possible to extend the existing and by placing between the names of each pair of
structure-based nomenclature beyond regular, sin- monomers an italicized connective to denote the
gle-strand polymers to polymers that have reacted, kind of arrangement by which those two types of
cross-linked polymers, ladder polymers, and other monomeric units are related in the structure.
more complicated systems. The structures listed in Table 1.6 are divided
into three categories: Short sequences, Long
1.2.2.2 Source-based Nomenclature sequences, and Networks. Within the fi rst category
a sequence of placement of individual CRU is
Traditionally, polymers have been named by considered, within the second the placement of
attaching the prefi x poly to the name of the long sequences of CRU defi nes the copolymer type,
CRU, real or assumed monomer, the source from while to the third belong crosslinked networks,
which it is derived. Thus PS is the polymer made crosslinked polymers, and chemical-type inter-
from styrene. When the name of the monomer penetrating polymer networks. The network is a
consists of two or more words, parentheses should crosslinked system in which macromolecules of
be used, but for common polymers such as poly- polymer A are crosslinked by macromolecules of
vinylchloride, polyvinylacetate, etc., it is custom- polymer B [Sperling, 1992]. The composition can be
ary to omit them. Different types of polymeriza- expressed as, e.g., block-co-poly(butadiene/styrene)
tion can take place with many monomers, and (75:25 wt%), or graft-co-poly[isoprene/ (isoprene;
there are different ways for obtaining a polymer. acrylonitrile)] (85:15 mole %).