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Dual Blade Cutter

The SER Advantage

As described in various publications and worldwide patents dating from 1998, the SER Universal Testing Platform marks a true breakthrough and paradigm shift in the field of melt rheometer technology. Not only has the SER created a buzz of excitement in the world of melt rheology but in the world of physical material characterization technology as well. However, looking to capitalize on the early and proven success of the SER, an imitation technology was introduced that was non-coincidentally similar in appearance but far less capable than the original model SER-HV. As described below, the SER offers significant performance advantages over this imitation technology.

SER Advantage #1

The imitation technology is incapable of a very important feature that is critical to ALL rheological measurements: strain validation. In an attempt to circumvent the U.S. and worldwide patented technology embodied in the SER, this imitation technology incorporates a secondary wind-up drum that orbits around a stationary wind-up drum, akin to the orbital motion of the moon relative to the earth, as shown below. Unlike the SER fixture that remains fixed while only the drums rotate, the imitation fixture assembly needs a lot of room as it twirls around within the oven and with its exposed gears presents a serious safety hazard to the skin and hands of the user operating anywhere near the fixture. Although the drum dimensions, securing clamp design, and sample geometry of this imitation technology are non-coincidentally identical to that of the SER, as a consequence of said orbital motion, the user has no clear access to the twirling sample as it undergoes deformation and hence real-time validation of the applied Hencky strain is near impossible.

   Top View of Imitation Technology   Top View of SER

Because only the drums of the SER rotate as shown above, the deformation zone remains in a fixed plane and the sample deformation can be visualized AT ALL TIMES regardless of the mode and kinematics of deformation , whether the SER is used in extensional melt rheology mode, solids tensile, tear, high-rate fracture, friction, or adhesion/peel testing modes. This is why the SER is able to provide such nice videos of sample deformations while the imitation technology cannot. Most notably, sample visualization is critical with the flow and deformation of any non-homogeneous polymer melt blends and compounds, semi-solid networks, foodstuffs, biomaterials, and solid composite materials where the assumption of bulk deformation uniformity is typically invalid due to the localized regions of strain deformation within the sample. Additionally, because the deformation remains in a fixed plane, only the SER can be utilized with optical characterization techniques such as flow birefringence and laser, neutron beam & x-ray light scattering during an experiment regardless of the mode (melt or solid) and kinematics (uniaxial extension, tear, peel, or high-rate fracture) of deformation.

SER Advantage #2

Another critical shortcoming of the imitation technology lies in the fact that because the primary and secondary drums are completely de-coupled, the imitation fixture can only be used on a rotational rheometer in which the torque transducer and motor are completely separate. Thus, the imitation fixture CANNOT be used with a controlled stress/strain rheometer – it can only be used on one platform, the TA/Rheometrics ARES rheometer which is the only controlled strain rheometer still available on the market. As has been described in several publications, the SER can be accommodated onto a multitude of host rheometer systems of either controlled strain or controlled stress/strain design. Hence, as new rheometer technologies are acquired in favor of or alongside other legacy rheometer systems, the SER can be easily adapted to accommodate the available laboratory rheometer equipment.

SER Advantage #3

Because its primary and secondary drums are de-coupled, ANY deformation with the imitation technology inherently places a potentially damaging lateral loading condition on the host rheometer’s torque transducer, as shown below. Due to the fact that the moment arm of the dangling stationary drum is much larger than the drum’s radius, the torque transducer signal is sensitive/susceptible to lateral loads particularly if a Bendix-type transducer is being used. Additionally, since the imitation fixture assembly twirls around with the motor, this lateral loading effect is typically translated non-symmetrically about the axis of the torque transducer as a function of motor rotation. Thus, factoring out these lateral load effects from the "true" torque signal response presents a host of concerns, particularly at high rates of deformation and at elevated stretching forces.

Lateral Load Condition with Imitation Technology

Because the primary and secondary windup drums of the SER are housed within a rigid chassis, the SER places NO such lateral load condition on the torque transducer. Hence, unlike the imitation technology that is limited to low tensile stress applications, the SER is capable of not only characterizing the extensional flow behavior of low viscosity polymer melts but is capable of measuring the physical behavior of high modulus solids.

SER Advantage #4

Another clear distinction of the SER's performance advantages lies in its remarkable versatility. Unlike the imitation technology, the SER is far more than just an extensional viscosity fixture. The SER's broad spectrum of physical material characterization capabilites allows the user the luxury and freedom to pursue much more, from extensional melt rheology to solids tensile, tear, peel/adhesion, friction, and high-rate fracture testing. The SER is an extremely versatile, miniature device that can do anything a conventional linear test frame can do with solids but at rates ORDERS OF MAGNITUDE higher and with samples weighing just a few milligrams! Because of its broad performance capabilities, the SER eliminates the need for expensive testing instruments and platforms that are far less capable with regard to rates of deformation and physical material characterization capabilities. The SER's breadth of capabilities with regard to extensional melt flow rheology characterization is showcased when hosted on a controlled stress/strain rheometer: transient extensional viscosity and cessation of extension results in the controlled rate mode of operation over a very broad range of Hencky strain rates is clearly exceptional, but tensile creep measurements in the controlled stress mode of operation even at low tensile creep stresses is remarkable.

SER Advantage #5

The launch of the SER2 model line back in 2007 introduced yet another clear advantage of SER technology over the imitation: detachable drums. Like the SER2, the new SER3 drums can be configured from any number of materials of construction, surface coatings and textures, as well as drum dimensions. Because the SER3 drums are fully detachable, polymer sample clean-up from the drum surfaces has never been easier - even for the most challenging of polymer residues, simply remove the drums and soak them in an appropriate solvent bath for complete sample removal. Whether its sample clean-up, improved sample gripping, or controlled surface properties measurements, the detachable drum feature of the SER3 model line gives the user tremendous flexibility and breadth of capability with regard to physical material characterization.

Detachable Drums

SER Advantage #6

Another dramatic advantage of SER technology lies in the fact that because both of the detachable drums are cantilevered and suspended from the SER base chassis, the SER3 models that are configured for use on controlled stress/strain rotational rheometers such as the SER3-P, SER3-G, SER3-T, and SER3-M are capable of fluid immersion testing. The drums of said SER3 models can be raised from and lowered into a controlled temperature fluid environment contained within a jacketed beaker or other such fluid containment vessel. Applications include biomaterials testing as well as high-temperature silicon oil bath testing to eliminate any effects associated with molten sample sag at low viscosities.

Detachable Drums

The SER Advantage

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