Lower cost analytical instruments aim for the Q-C user.

There were over 1080 exhibitors at this year's Pittsburgh Conference, the largest analytica-instrument show in the world, which was held in Chicago in March. Increased attention to routine quality-assurance testing was identified as a major trend in plastics by several suppliers interviewed at the show. That may explain why many suppliers have focused their recent efforts on designing instruments for q-c/q-a environments more than for R&D labs. More often than not, the new instruments very nearly approach the performance of their higher-end, research-grade counterparts but are considerably lower in cost. This trend was evident in much of the new instrumentation displayed, particularly in the areas of thermal analysis and rheology measurement. Several of the instruments are offered with enhanced user-friendly software, often for a Windows environment.

THERMAL ANALYSIS NEWS

The most widely used thermal-analysis technique for q-c applications is differential scanning calorimetry (DSC). Some of the new DSC instruments can be had for under $20,000, as compared with $30,000-35,000 just a few years ago. For example, Perkin-Elmer Corp., Norwalk, Conn. introduced the DSC 6, its new low-cost instrument, which provides complete control and calibration via a PC keyboard. The unit utilizes Microsoft Windows software and has a "zoom" feature that allows the data to be rescaled in real time. It sells for $16,000 with software and $18,000 with a 486 PC.

Also geared to q-c applications is a new thermal analyzer from Astra Scientific International, Inc., Pleasanton, Calif., which features multi-module operation so that thermogravimetric analysis (TGA), differential thermal analysis (DTA), and DSC can all be operated simultaneously. Called "Setaram Labsys TGA/DTA/DSC," the system features Windows software and is priced in the range of $20,000-40,000, depending on modules and temperature range required.

Shimadzu Scientitic Instruments, Inc., Columbia, Md., showed an enhanced version of its TA-50WS Windows-based software for thermal analysis, which includes specific heat and stress/strain analysis. The company also revealed plans to offer a lower-cost, simultaneous DSC/TGA thermal analyzer early next year. It will be designed to process small sample quantities and will be priced around $25,000. But Shimadzu expects to launch even sooner a new "high-mass" instrument, the TGA-51, which can handle large samples--up to 15 g, rather than milligram quantities.

Two more lower-cost systems were among the new products introduced by TA Instruments, Inc., New Castle, Del. DSC 2010 is a compact, automated benchtop system, priced at $30,000--about half the cost of research-grade DSCs, but with high sensitivity (1.0 microwatt) and a wide temperature range (-180 to 725 C) . The new TGA 2050, based on a reportedly unique vertical-balance/horizontal-purge design, has a sensitivity of 0.2 |Mu^W and relatively large sample capacity (1 g), as well as a broad temperature range (ambient to 1000 C). It sells for around $37,000, as compared with research-grade units that run $50,000-55,000. Both instruments come with a 386 PC controller and eight-pen color plotter.

TA Instruments also showed the DSC 2920, a new high-performance instrument with sensitivity of 0.2 |Mu^W and interchangeable cells. It's priced at $55,000.

Both TA Instruments and Seiko Instruments USA, Inc., Elk Grove Village, Ill., are offering new TGA/mass-spectrometer (MS) combination systems for complete evaluation of evolved decomposition gases.

Through its recent acquisition of the Thermal Sciences Div. of England's Polymer Laboratories, Rheometrics Inc., Piscataway, N.J., offers the new DSC Plus, an "intelligent" DSC that plugs into an IBM PC or compatible to provide a complete working system. The compact, transportable instrument has all the features of Thermal Sciences' established top-of-the-line DSC, including a range of interchangeable cells that offer very high sensitivity (sub-microwatt) and pressure capability up to 1200 psi. It comes with a 486 computer and color plotter.

Rheometrics also showed a low-cost version of DSC Plus, the DSC QC, which operates on a stand-alone basis for q-c applications but utilizes the same sensitive cell. It comes with a PC and basic software, which can be upgraded to multi-module testing capability. Prices for the instruments alone start at $20,000 and go up to $35,000 for a complete system.

FOR RHEOLOGICAL TESTING

Bohlin Instruments, Cranbury, N.J., is now offering the DSR-F (Dynamic Shear Rheometer-Fluids Rheometer) in the U.S. It's a low-priced instrument designed for users that require more than a simple viscometer but not the sophistication of research-grade rheometers. The instrument can measure viscoelastic properties of samples from low-viscosity fluids to semi-solid polymers. Key features include steady-shear software and a cone/plate measuring system; controlled-shear-stress and shear-rate modes; and a sealed casing to prevent accidental damage. It sells for around $40,000, whereas research-grade instruments cost $100,000-150,000.

Bohlin also showed the Bohlin CVO melt rheometer, said to represent the next generation of research rheometers because of its modularity and enhanced measuring range. It accommodates a wide range of applications from low-viscosity fluids to stiff pastes or semi-solid materials. Features include creep, viscometry, and oscillatory testing software; controlled-shear and shear-rate modes; wide torque range; high angular-positional resolution for low-strain nondestructive measurements; and high-speed capability for high-shear measurements. Available with DOS or Windows software, the CVO is priced between $70,000 and $90,000.

Haake, Inc., Paramus, N.J., exhibited recent enhancements to its RheoStress RS 100 rheometer, including a high-temperature, high-torque option for high-performance polymers. Operating temperature for the standard unit ranges from -50 to 350 C, and up to 500 C for the new high-temperature option. Another new option is time/temperature-superposition software, which allows the user to obtain all types of molecular-weight and MW-distribution data, as well as to obtain shear rates above and below the operational shear rate of the instrument. The RS 100 is priced in the range of $50,000-70,000--the high end includes the high-temperature, high-torque unit and new software.

Rheometrics launched two automatic sample-loading features--AutoZero and AutoGap--for its Dynamic Stress Rheometer (models SR-200 and SR-500). They are said to improve data reproducibility and to be especially useful in high-productivity q-a/q-c environments with multiple operators running repetitive tests.

TA Instruments introduced Rheology for Windows, a new software package for its CSL(2) Controlled Stress/Controlled Rate Rheometer. It's available in several versions including one or more of the standard rheological modes of operation--flow, creep, and oscillation.

Custom Scientific Instruments, Cedar Knolls, N.J., showed the MF12 melt-flow indexer, a new extrusion plastometer that provides basic melt-flow measurements of thermoplastics. An on-board computer provides push-button calibration and temperature control within |+ or -^0.2|degrees^ F. A programmable optical encoder provides precisely adjustable piston travel for keyboard programming of multiple extrusions.

NEAR-INFRARED SPECTROSCOPY

The newest FT-IR spectrometer for near-infrared (NIR) measurement is the Paragon 1000 from Perkin-Elmer. It is based on the widely used Model 1600 but reportedly combines lower cost with excellent sensitivity and resolution. Geared primarily to q-c applications, its performance is said to surpass that of the research-grade spectrometers of a decade ago. With Windows-based software, it sells for about $22,000.

Bran & Luebbe, Inc., Buffalo Grove, Ill., introduced InfraProve II, a high-precision NIR instrument for identification and quantitative analysis of incoming raw materials or monitoring formulations in process. The unit has a small, handheld fiber-optic probe. The instrument, probe, PC, and software sell for around $80,000.

LT Industries, Inc., Rockville, Md., featured new and reportedly user-friendly software for its NIR polyol analyzer system used to measure the hydroxyl value and acid number of urethane polyols both in the lab and for on-line process control. New "Overview" software allows users to customize screens. The NIR Polyol Analyzer system--spectrometer, sample device, PC, new software, and LT-supplied calibration--is priced at about $65,000.

Spectra-Tech Inc., Stamford, Conn., showed a new computer-controlled, motorized FT-IR sampling accessory, the Sample Wheel, for unattended transmission analyses of multiple solid samples. It comes in two versions with either 15 or 30 sample positions. It is priced around $5000.

X-RAY ANALYSIS

One less familiar analytical method for plastics also made news at PittCon. Diano Corp., Woburn, Mass., is offering a lower cost x-ray diffractometer for nondestructive material identification. Optimized for industrial process control, the new 2100 E sells for under $60,000 including software, while traditional x-ray diffractometers are priced in the $90,000-100,000 range.

Applications for this instrument in plastics include identifying pigments and obtaining quantitative and qualitative data on a polymer's degree of crystallinity. The 2100E x-ray diffractometer is designed to work in conjunction with an x-ray spectrometer, which provides elemental analysis. For example, the spectrometer can measure the content of titanium metal to indicate how much Ti|O.sub.2^ is in a product. Diano is now offering a combination package of the two instruments for under $100,000, which reportedly makes it cost-effective for labs that have only moderate volume demands.

NEWS IN GPC 

Polymer Laboratories' Separation Science Div., Amherst, Mass., brought out a dedicated high-temperature gel-permeation chromatography (GPC) system that uses a high-sensitivity i-r detector for analyzing a wide range of polymer molecular weights. It's extended temperature capability (to 400 F) expands the applicability of the unit to characterization of high-performance engineering materials. It's standard use is for polyolefin analysis at typical temperatures of 285-320 F. It is priced at $70,000.