PEL PLASTICS UPDATE highlights recent progress in key areas of polymer/plastics technology including: catalysis, biopolymers, smart/functional polymers, alloys & blends and polymer modification. A recent issue of PEL Plastics Update follows.

Complimentary Copy
Vol. 6, No. 5
PEL PLASTICS UPDATE
Jan.-Feb., 1999
By Mort Wallach
ISSN 1094-656X
 

Nanocomposites/Automotive-New TPO clay nanocomposites from GM/Montell have application in automotive interior and exterior panels and provide significant benefits including reduced weight and better dimensional stability as well as improved stiffness and low temperature impact resistance. Meanwhile, AlliedSignal with BMW and MercedesChrysler are developing a high performance PET grade for exterior body panels which are expected to be competitive with widely used Noryl GTX.

• General Motors and Montell have developed new thermoplastic polyolefin nanocomposites with significant advantages over traditional thermoplastic materials and fillers such as talc, mica, and CaCO₃. The new TPO-based nanocomposites contain 5% smectite clay exfoliated in TPO which provides stiffness characteristics equivalent to 25-35% talc-filled material. New prototype rear quarter and exterior door panels were produced with this technology. GM suggests that nanocomposites may well have a significant impact on the manufacture of automobiles.
  (Plastics Engineering, Feb. 1999, p. 46)

   

• AlliedSignal working with BMW and MercedesChrysler is well along in developing a High Performance Petra PET grade for exterior auto body panels. The compound made from recycled soda bottles is reported to withstand temperatures of 200°C in paint ovens which is better than Noryl GTX PPE/nylon blends that dominate the market. The material can withstand impacts without creating sharp-edge splinters as unmodified PET can do. Qualified PET recyclers have already been selected and molders are now sampling material for pre-series production.
  (Modern Plastics, Feb. 1999, p. 18)

Biodegradable Polymers-Niche markets are emerging, new plants are coming on-stream, and biodegradable materials are being developed with properties similar to polyethylene, polypropylene, PET, PVC, etc. Also legislation in both Europe and Japan are favoring wider use of biodegradable polymers. Key materials, which offer the potential for the required lower competitive prices include polylactic acid (PLA) and aliphatic/aromatic polyesters.

• Possibilities are expanding including Bayer's novel biodegradable polyester amide which can be injection molded or extruded. It is made from hexamethylene diamine, butane diol, and adipic acid. Target markets include trash bags, plant pots, food packaging, and disposable utensils. Cargill Dow Polymers is the leader in PLA which is based on renewable agricultural resources such as corn or sugar beets. The targeted polymer is clear and has good moisture resistance, stiffness, and gloss, with flavor and odor-barrier properties similar to PET. Applications include blown and biaxially oriented films, rigid containers and coatings. Eastman Chemical offers a copolyester with uses in lawn and garden bags, food packaging, and horticultural applications. It is a semi-crystalline transparent film with modulus lower than PE, but with better oxygen-barrier properties. BASF has a biodegradable copolyester with properties comparable to LDPE. Films are tear and water-resistant but unlike LDPE they allow permeation to water vapor. DuPont announced the commercial release last year of Biomax hydro/biodegradable polyester which is only slightly more expensive to produce than PET. Properties are: M.Pt. 200°C, E 50-500%, with tensile strength of up to half that of Mylar. Environmental Polymers Group in London is developing special grades of polyvinyl alcohol which are biodegradable in hot or cold water. These grades are amenable to extrusion processing. Films have equivalent or better properties than PVC or PE. Metabolix in Cambridge produces polyhydroxy- alcanoates (PHA) via transgenic technology developed internally. The PHA can be produced directly by photosynthesis or indirectly by the fermentation of sugars. Target markets include single use medical devices and fast food restaurant serviceware. In particular, polyhydroxybutyrate is a very crystalline thermoplastic with many properties like PP including M.Pt., tensile strength, T_g, and crystallinity.
  (M. Defosse, Modern Plastics, Jan. 1999, p. 32)

Smart/Functional Polymers-Bell Labs is developing holographic polymer film systems for high volume data storage which overcome some of the limitations of traditional LiNbO₃ based systems.

• M. Cardillo and A. Harris of Lucent's Bell Labs are preparing these photo-polymer films by partially polymerizing an oligomer-monomer system via illumination between glass plates. During subsequent recording, some unreacted monomer undergoes gelation in a spatially modulated pattern by subjecting the system to the interference pattern from two laser beams, one of which carries the information. An irreversible refractive index grating is created that encodes the information in the polymer when the residual unreacted monomers diffuse to other sites and are locked into place by polymerization. Typical formulations include a mixture of difunctional acrylate oligomer, N-vinylcarbazole and isobornyl acrylate monomer, and a photoinitiator. High storage densities of 480 KB/page were achieved via multiplexing. Information retrieval was obtained with low bit-error rates. With new materials they have achieved up to 50 GB storage on a 5 1/4 inch disk with a commercialization goal of 100-200 GB. Other interesting work is proceeding at Bell Labs on plastic transistors and plastic optical fibers. (Opt., Let. 23, 7910, 1998)

Alloys & Blends-Various oxazoline (OX) functionalized olefin polymers (e.g., PP/OX and PE/OX) were demonstrated to be effective compatibilizers of PP/N6, PE/N6, and PP/PBT blends. Also, it was shown that PBT could be impact modified with appropriate ABS materials.

• C. Vocke and coworkers at the University of Technology in Helsinki have recently studied OX functionalized PP, PE, E/P copolymer, and SEBS, as compatibilizers in blends of PP/polyamide 6, PP/PBT, and PE/polyamide 6 with engineering thermoplastics contents of 30 wt %. The blends were prepared in a twin screw extruder, and then injection molded. Compatibilization substantially improved the toughness of all tested blends while retaining strength and stiffness. As expected when using elastomeric compatibilizers, stiffness levels decreased slightly. Morphology studies showed that the particle size was reduced and the adhesion of the dispersed phase to the matrix was improved by compatibilization.
  (J. Appl. Polym. Sci., 70(10), 1923, 1998)

   

• D. Paul and coworkers at the University of Texas in Austin demonstrated that terpolymers of MMA/GMA/EtA (methyl methacrylate/glycidyl methacrylate/ethyl acrylate) are effective reactive compatibilizers for blends of PBT with ABS or SAN copolymers. Evidence was presented for reaction between the polyester carboxyl end groups with GMA to form a graft copolymer during melt processing. Moderate amounts of GMA in the terpolymer (>5%) and small amounts of compatibilizer in the blend (<5%) were found to significantly improve SAN dispersion. A preliminary investigation into the effect of this compatibilizer on PBT/ABS morphology and impact properties revealed greatly improved toughener dispersion and low temperature toughness. (Polymer, 40(2), 365, 1998)

Alloy & Blend Patents-Among 1000 patents reviewed during this period, there are several noteworthy inventions involving: Mg(OH)₂ FR reinforced polyamide, toughened polyketone, tailored glass filled polyester for molding, and syndiotactic polystyrene foam.

• "Magnesium Hydroxide-Fireproofed And Fiber-Reinforced Polyamide Compositions With Excellent Thermal Stability And Their Preparation". K. Onishi et. al. (Toray Industries) JP 11 21,447, Jan. 26, 1999. Title compositions with suppressed decomposition during prolonged residence in a mold contain polyamide matrices which consist of >2 different polyamides with different concentrations of amide groups (calculated as C no. per amide group), where >50% Mg(OH)₂ is in polyamides other than those with the highest concentration of amide groups. Mg(OH)₂ is mixed with polyamides with lower amide concentration and then other polyamides with higher amide concentration and reinforcement fibers are added to the mixtures to prepare the compositions. Thus, 24 parts nylon 610 and 47 parts Kisuma 5E were melt kneaded to obtain master pellets, which were then melt kneaded with 14 parts nylon 66 and 15 parts glass fibers to give a composition showing no bubble formation when it was kept at 280°C for 5 min. Test pieces prepared from the composition showed tensile strength 22 J/m, and UL-94 fire resistance rating (1/16") V-0. (Chem. Abs. 130: 125895e)

   

• "Toughened Polyketone Composition Comprising An SAN-Grafted Polyolefinic Rubber And Molded Or Extruded Articles Therefrom". J. Bonner (BP Chemicals Limited) PCT Int. Appl. WO 98 54,262, Dec. 3, 1998. A toughened polymer composition comprises a major amount of a polyketone having a linear alternating structure of (a) units derived from carbon monoxide and (b) units derived from one or more olefinically unsaturated compounds, and a minor amount of a graft copolymer having a polyolefinic elastomeric backbone such as EDPM with a glass transition temperature < 0°C grafted with a styrene/acrylonitrile (SAN) resin. Thus, a polymer blend comprising an ethylene-propylene-carbon monoxide polyketone and 20 wt% of Royaltuf 372P20, extruded, compounded, and compression-molded gives Izod impact strength (ASTM D 256) of 38 J/m at -40°C and no break at 23°C compared to 18 and 122 J/m respectively, for a composition without Royaltuf 372P20.
  (Chem. Abs. 130: 67210q)

   

• "Glass Filled Polyester Molding Composition For Molding Of Reduced Warpage With Improved Impact Strength". P. Vollenberg et. al. (General Electric Co.) US 5,840,798, Nov. 24, 1998. A reinforced polyester molding composition comprises a polyester resin such as poly(alkylene terephthalate) and glass fibers which have a bimodal cross sectional area where a smaller cross sectional area is selected to improve impact strength and a larger cross sectional area is selected to improve warpage and diameters of the smaller diameter fibers to the larger diameter fibers ratio < 0.8 and the distribution of larger diameter fibers to smaller diameter fibers is 55-90/20-45. A blend of glass fiber (10 µm) 8.0, glass fiber (14 µm) 7.0, polycarbonate 5.0, poly(butylene terephthalate) 33.35, PET 15.8, BaSO₄ 30.0, antioxidant 0.20, PE-18 0.20, Tinuvin 234 0.30, and ZnHPO₄ 0.15% was molded into test pieces having warpage 11.8 mm, unnotched Izod impact strength no value, and tensile strength 13,000 psi. (Chem. Abs. 130: 25780v)

   

• "Syndiotactic Styrene Polymer Foam Having Improved Heat Resistance And Mechanical Properties". K. Suh et. al. (Dow Chemical Co.) PCT Int. Appl. WO 99 03,919, Jan. 28, 1999. Title foam is obtained from a polymer blend comprising a syndiotactic styrene polymer and an amount of an amorphous polymeric material which will impart a heat distortion temperature >130°C. Thus, a composition comprising 60% syndiotactic polystyrene and 40% maleic anhydride-modified polyphenylene oxide gave a foam having density 3.60 pcf, cell size 0.75 mm, and heat distortion temperature > 200°C, compared with 4.25, 1.62, and 80, respectively, for 100% syndiotactic polystyrene foam. (Chem. Abs. 130: 126081y)

New Ventures/Products-Dow Chemical and BASF are focusing on new plastic product development in 1999 as compared to prior emphasis on cost cutting. Sales volumes are expected to be up 13%, and as much as 25%, respectively.

Top managers at Dow and BASF are reportedly planning to expand their way into prosperity this year as compared to employing only cost-cutting measures. Rather than too much productivity emphasis, R & D and new product development strategies are being focused on more. In line with this approach Dow Plastics is spending about $300 million on R&D in 1999. Recent new polymers from Dow include ethylene-styrene copolymers (Index) achieved via the Insite single-site constrained geometry catalysis. Insite catalysts are also the route to syndiotactic polystyrene (Questra) which will compete in the midrange engineering resin spectrum. Also, Insite-catalyzed polyethylene (Elite) is expected to be about 10% of Dow's polyethylene sales in 1999 with a doubling of sales expected annually. Plans are underway to increase Index and Questra production to commercial scale. Index, with higher product value than typical polymers based on ethylene or styrene alone is expected to sell at about two times the latter polymers (e.g., 75-90/lb). For the same reasons Elite resins are expected to be less vulnerable to price changes then typical polyethylenes. This strategy should help overcome situations like 1998 performance for Dow Plastics including higher sales volume over 1997 with lower sales value resulting in a 10% pricing drop. This was particularly serious since Dow Plastics represents more than half of Dow Chemical's sales. Sales volume is expected to be up 13% this year mainly due to increased PP and PE capacity with pricing no better than last year. Scarce investment capital should go to higher return technology based products such as engineering resins. These include the recent additions to Dow's line such as nylon, PP, and Questra to go with existing products PC and ABS. In this area Dow enjoyed 30% volume growth in 1998. Dow is not ignoring costs having cut $2 billion since 1995 and expecting to cut $700 million more by 2000, but Dow feels that they are getting close to the point of diminishing returns via cost cutting as compared to growth via technology based products to meet customer needs. Meanwhile BASF's plastics materials group-which manufactures nylon, acetal, and styrenic copolymers and markets several other engineering plastics including PBT-expects good growth in nylon, PBT, and specialty styrenics (where a new copolymer plant is starting up this quarter). BASF predicts that North American engineering plastics sales will increase as much as 25% this year. As the leader in ASA (acrylic-styrene-acrylonitrile) in North America BASF is promoting a coextruded ASA/ABS composite wherein ASA provides light stability and good surface appearance and ABS provides impact and temperature resistance. They expect this development to expand the ASA market by as much as 15%. Growth would come by replacement of fiberglass reinforced polyester, and aluminum in large volume applications such as truck trailers, pool shells, patios, and power boats.
(M. McCoy, C&EN, Jan. 11, 1999, p. 20)