Bi-Monthly
Newsletter
PEL PLASTICS UPDATE highlights recent progress in key areas of
polymer/plastics technology including: catalysis, biopolymers, smart/functional
polymers, alloys & blends, nanotechnology, polymer modification and new
ventures. A recent issue of PEL Plastics Update follows.
MILLENNIUM ISSUE
Vol. 7, No. 3
PEL PLASTICS UPDATE
Jan.-Feb., 2000
By Mort Wallach
ISSN 1094-656X
RECENT PROGRESS IN POLYMER/PLASTICS TECHNOLOGY
Polymers and Plastics in the 21st Century-As we enter the new
millennium a number of key issues and technical advances are on the horizon
involving implementation of biotechnology, development of green processes and
products, new material designs for the automotive industry, innovations targeted
for the IT revolution, nanotechnology for applications in medicine, industry and
defense, and E-commerce to enhance profitability and globalization.
1. Implementation of Biotechnology: Utilization of renewable resources
and biotechnology to alleviate dependence on petrochemicals and natural
gas-based systems will be a key activity, creating new monomers and polymers via
bacterial fermentation and genetically engineered processes.
2. Development of Green Processes & Products: Design of cleaner
manufacturing plants, new biodegradable polymers, use of supercritical
polymerization media such as supercritical CO2
are making headway and should continue.
3. New Material Designs for the Automotive Industry: Lighter/stronger
composites, new modular designs, and class A finish materials, all of which will
be recyclable will be a major goal in automotive.
4. Innovations Targeted for the IT Revolution: Development of polymer
lasers, flexible thin film circuits for computers, polymers for smaller/denser
faster chips, and quicker switches, improved displays (e.g., LEDs), and new and
improved CMP for more complex circuit layering are among the areas enhancing the
IT revolution, and should power the economy further.
5. Nanotechnology: Applications to stronger polymeric materials in
composites and coatings, better packaging films, miniaturized electronic and
photonic devices, and new biotech nanoadvances including dendrimers for gene
therapy, in-vivo drug release, and enhanced prosthesis should be among many
developments made possible via nanotechnology. We expect nanotechnology to be a
leading area of important innovations in the new millennium.
6. Use of E-Commerce to Enhance Profitability and Globalization:
Worldwide customer interface, rapid response, tailored products, lower inventory
requirements, and lower costs are routes to polymer and plastics business
success in the new century.
Nanocomposites-New nanocomposite fluoropolymer-silica coatings
were prepared via the sol-gel process to yield glass adhering systems which have
potential in antifouling, photolithog- raphic patterning, and protection from
moisture. These coating systems could be applied to metal oxide surfaces (e.g.,
aluminum, iron, platinum) which heretofore have been difficult to coat with
hydrophobic materials.
- A. Stiegman and coworkers at Florida State U. in Tallahassee have
succeeded in coating fluoropolymers which are hydrophobic on to glass which is
hydrophilic. Their method incorporates fluoropolymers into porous inorganic
films made by the sol-gel process which can produce hard and porous xerogels.
The glass adhering properties of silica and the catalytic features of vanadia
were employed by spreading a film of sol onto a quartz surface and then
topping the film with a thin layer of difluoroethylene liquid. The surface is
bombarded with UV light causing the vanadia to polymerize the difluoroethylene
in the pores of the xerogel from which polymer spreads out in a layer over the
surface. This results in a polyvinylidene fluoride-silica nanocomposite
coating which is very strong and has a surface energy close to pure
polyvinylfluoride. This is a first demonstration of good adhesion of a
fluoropolymer on ceramic oxide surface. Oxide coated aluminum, iron, platinum
and other metals could presumably be so coated. Applications include enhanced
parts for automotive, aerospace, marine and defense. (J. Phys. Chem. B, 103,
9383, 1999)
Smart/Functional Polymers-New dendritic polymers were developed
which harvest light of varied wavelengths and efficiently convert the radiant
energy to blue light leading to potential applications in optoelectronic devices
such as molecular wires.
- Prof. T. Aida and coworkers at U. of Tokyo prepared rigid rods of
poly(phenylethynylene) (PPE) conjugated backbone wrapped with a flexible
poly(benzyl ether) dendritic envelope. The backbone collects visible light and
the envelope collects photons of UV light and channels the energy to the
backbone which then fluoresces blue. The quantum yield is high (i.e., photons
converted to fluorescence) as is the energy transfer from the light-harvesting
antennae of the dendritic envelope to the chromophore units. Fluorescence of
the backbone is most intense when it is encapsulated by third generation
dendritic wedges. Shielding by the dendritic wedges enhances the fluorescence
unlike poly(phenyleneethynylene) without the wrapping which undergoes
collisional quenching of the photoexcited state. The dendritic envelope
prevents these collisions (i.e., "the envelope effect") moreso with each
generation of dendritic wedges. The high efficiency and blue emission give
more interest to this work. The PPE being very rigid is not very soluble and
is difficult to process whereas the dendritic material is quite soluble in
solvents such as THF at MWt of 250,000. Photo- and redox- functionality at
backbone terminals are being investigated with the goal to prepare molecular
wires. (J. Am. Chem. Soc., 121, 10658, 1999)
Catalysis-New robust Ni based catalysts which yield high
molecular weight polyethylenes, function at low temperature and pressure, do not
require a cocatalyst, can tolerate contaminants, and can polymerize olefins with
functional groups.
- Prof. R. Grubbs and coworkers at Cal. Tech. have demonstrated these
catalysts which are unlike metallocenes which require very clean conditions,
and are susceptible to inactivation by organic functional groups and
impurities (e.g., O2 , N), and are unlike the
Shell higher olefin process (SHOP) which primarily makes oligomers (4-20
units) and requires high temperatures and pressures. The Grubbs strategy
starts with the SHOP catalyst replacing the phosphorous-oxygen ligand based
species with one based on the more sterically bulky salicylaldimine. The Cal.
Tech. team obtained polyethylene with MW=250,000, narrow molecular weight
distribution, and very little branching. They also produced copolymers of
ethylene and olefins functionalized with polar groups such as hydroxyl. This
development builds on past work and is an advance in understanding
transition-metal olefiin polymerization catalysis with meaningful industrial
potential. (Science, 287, 460, 2000)
Alloys & Blends-Functional elastomeric approaches can enhance
the performance of high impact polystyrene (HIPS) to make it an economical
alternative to ABS. Atom transfer radical polymerization (ATRP) of end
functional polystyrene (PS) can be melt processed to N6/PS blends with improved
properties. Also, toughened poly(phenylene sulfide) (PPS) is being developed
with applications targeted in electrical and automotive parts.
- Firestone Polymers has attached functional groups to rubber, to
better adhere polybutadiene or styrene-butadiene in HIPS. This approach which
had been used by Bridgestone/Firestone, to enhance rubber bondability to
carbon black improving tire performance could also boost the performance of
HIPS, making it an economical alternative to ABS and other resins. Target
end-uses include packaging where functionalized rubber-based HIPS would offer
better stress crack resistance and high clarity. Interest in functionalized
rubber toughening technology is high among resin makers. (Modern Plastics,
Oct., 1999, p. 14)
- E. Koulouri and coworkers at U. Patras in Patras, Greece and U. of
Groningen, Netherlands synthesized terminal maleic anhydride
functionalized polystyrenes using ATRP. Melt mixing of these reactive
polystyrenes with nylon 6 resulted in blends with good mechanical properties
attributed to an in situ formation of a copolymer which may be used for the
compatibilization of the binary nylon 6/polystyrene blend. The mechanical
properties of the resulting ternary blends were significantly improved with
the addition of the modified polystyrene. The enhanced mechanical properties,
as well as the fine PS dispersion in the nylon 6 matrix (revealed by SEM of
the compatibilized cryofractured samples) support the hypothesis that an
effective compatibilization of nylon 6/PS was achieved. (Macromolecules, 32,
6242, 1999)
- K. Kubo and coworkers at Asahi Chemical Industry in Kawasaki, Japan
have made advances in toughening PPS. Chemical treatment was employed to
activate the reactivity of the PPS end-group via extrusion in the presence of
diphenylmethane diisocyanate (MDI). Reactive processing of the MDI-treated PPS
with an olefinic elastomer containing a functional group such as carboxylic
acid anhydride gave toughened PPS. The elastomer was finely dispersed in the
matrix. Lamination of MDI-treated PPS sheet and the functional olefinic
elastomer sheet exhibited strong adhesion. Viscoelastic properties and melt
viscosity measurements suggest a strong interaction between the two sheets.
Toughened PPS is used in electrical/electronic and automobile parts requiring
high performance. (Kobunshi Ronbunshu, 56(7), 426, 1999)
Alloy & Blend Patents-Among 1500 patents reviewed during this
period, there are several noteworthy inventions involving: polyolefin
nanocomposites, paintable TPO compositions, and polyvinylidene fluoride blends
with imide containing polymers.
- "Polyolefin Nanocomposites". M. Alexandre et. al. (Dow Chemical
Co.) PCT Int. Appl. WO 99 47,598, Sept. 23, 1999. A nanocomposite is a
dispersion of nanofiller particles derived from layered metal oxides or metal
oxide salts. The nanocomposite is advantageously prepared by first swelling an
untreated clay in water, then removing the water to form an organophilic clay
that is dispersible in non-polar organic solvents. The organophilic clay can
then be treated with an alkyl aluminoxane and subsequently a catalyst to form
a complex that promotes olefin or styrenic polymerization and platelet
dispersion. The nanocomposite can be prepared directly by in situ
polymerization of olefin or styrene at the nanofiller particles without shear,
without an ion exchange step, and without the need to incorporate polar
substituents into polyolefin or polystyrene. (Chem. Abs. 131: 229867j)
- "Directly Paintable Thermoplastic Olefin Composition Containing Maleic
Anhydride-Modified Polymers And Injection-Molded Articles Therefrom". D.
Berta (Montell NA, Inc.) US 5,959,030, Sept. 28, 1999. Directly paintable
polymer compositions contain (1) a thermoplastic olefin (TPO), (2) a maleic
anhydride-grafted propylene homopolymer or random copolymer, (3) a maleic
anhydride-grafted olefin polymer material, (4) a functionalized polymer that
reacts with the maleic anhydride groups of the grafted polymers, and,
optionally, (5) a maleic anhydride-grafted ethylene polymer. The amount of (2)
+ (3) or (2) + (3) + (5) is 16-27 parts/100 parts of the TPO. Thus, an
injection molded disc comprising TPO 100, Exxelor VA 1803 (I) 5, Royaltuf 465A
(II) 5, maleated polypropylene 10, Jeffamine XTJ 418 3, and antioxidant 0.2
part showed paint adhesion (paint removed with adhesive tape) 3%, and
durability (paint removed with Tabor abrader, 1 lb load) after 25 cycles 10%
and after 50 cycles 20%, compared with 0, 0, and 0, respectively, when the
molding also contained 5 parts Ceramer 67; and 45, 28, and 44 respectively,
for a molding containing 10 parts Dutral 4038 instead of I and II. (Chem. Abs.
131: 244127m)
- "Compatible Polyvinylidene Fluoride Blends With Polymers Containing
Imide Moieties". S-C. Lin et. al. (Ausimont USA, Inc.) US 5,959,022, Sept.
28, 1999. A compatible blend of superior mechanical strength, hardness and
abrasion or mar resistance comprises PVDF and a compatible organic polymer
containing > 1 imide group (e.g., N- cyclohexyl maleimide-Me methacrylate
copolymer). The alloy is prepared by dissolving, separately, the PVDF and
polymer in a solvent and blending the solutions to provide the required
composition. The alloy can also be prepared by dispersing PVDF powder in a
solution of polymer containing imide groups. After heating and drying, a
homogeneous alloy is formed. In addition, melt extrusion of PVDF with the
imide-containing polymer also generates the desired PVDF alloy. (Chem. Abs.
131: 244126k)
New Plastics Ventures- Shell Petroleum and BASF are combining
their polyolefin businesses to form one of the largest such operations
worldwide. Cyclics Corp., a new company will produce polymer composites of
polycarbonate, polyarylate, and PBT from low molecular weight cyclic oligomers
which readily polymerize and possess good reinforcement wet-out. Applications
include auto parts, bicycle frames, and bridges.
Shell Petroleum, part of the Royal Dutch Shell Group and BASF A.G. are
joining their polyolefins businesses to form one of the largest polymer
operations. Combined revenues are more than $6 billion. This venture would rank
first in polypropylene and fourth in polyethylene worldwide. BASF and Shell plan
to combine their Elenac, Montell, and Targor businesses. Elenac is the
polyethylene alliance of the two companies headquartered in Strasbourg, France.
Montell headquartered near Amsterdam is currently the world's leading producer
of polypropylene. Targor based in Mainz, Germany, is a joint venture of BASF and
Celanese who is looking to focus more on it's specialty business, and has agreed
to sell it's 50% stake in the Targor polypropylene business to BASF for more
than $260 million. Since Montell and Targor are among the leading polypropylene
producers, antitrust issues may arise and industry observers suggest that the
companies may have to divest capacity in Europe. Polyethylene is not considered
a problem since Equistar, Dow, and Exxon have larger market shares. Shell and
BASF would share ownership of the polyolefin operations which will be based in
the Netherlands. (A. Thayer, C&EN, Nov. 8, 1999, p. 8)
Cyclics Corp., Schenectady, N.Y. (a new firm) purchased ~50 U.S. and
foreign patents from General Electric Co. covering cylic compositions of
polycarbonate, polyarylate, and PBT polyester. These low molecular weight
oligomers readily process into high molecular weight thermoplastics. Since their
initial viscosity is low, fiber reinforcement penetration is good for making
thermoplastic composites. The technology combines the processability of a
thermoset with the material properties of a thermoplastic. Cyclic PBT can be
polymerized in seconds without exotherm so that parts can be demolded quickly
without cooling. The company is setting up facilities near Albany, NY and
experimental quantities of cyclic resins are expected in a few months. Potential
composite applications include: auto parts, bicycle frames and bridges.
(Plastics Technology, Sept., 1999, p. 29)
Top of Page
Previous
Newsletters
|