A Modular Peel Fixture for Tape Peel Tests on Immovable Substrates

Background

Peel tests are frequently used to perform measurements of adhesive strength for pressure sensitive adhesive (PSA) tapes. Current lab methodologies for 90° peel tests translate the model substrate orthogonally to the peel direction in order to maintain the peel angle, precluding testing from immovable substrates.

Objective

It was our objective to develop a peel fixture capable of testing temporary pavement marking (TPM) tapes and other PSA tapes from immovable substrates such as roadways surfaces.

Methods

We present a modular peel fixture for conducting peel experiments directly on immovable substrates. The fixture was validated through a series of peel tests on consumer tapes to reproduce the linear width dependence and viscoelastic rate dependence found in traditional peeling setups. To test the capabilities of the fixture, a series of peel tests were conducted with various tapes on controlled surfaces, and a commercial tape on various immovable substrates.

Results

We demonstrate the ability of our fixture to reproduce results reported for traditional peel tests from literature. In addition, we were able to conduct peel tests directly on immovable substrates such as the benchtop.

Conclusions

This fixture shows potential for both traditional peeling tests, and for use in in-situ peel experiments from substrates relevant to the end application of the PSA tape.

     

Dynamics of Narrow Tilting Vehicles

Narrow commuter vehicles can address many congestion, parking and pollution issues associated with urban transportation. In making narrow vehicles safe, comfortable and acceptable to the public, active tilt control systems are likely to play a crucial role. This paper concentrates on developing a dynamic model for narrow vehicles that can be used for the design and evaluation of active tilt control systems. The model has four degrees of freedom including lateral and tilt dynamics. The influence of gyroscopic forces due to rotating wheels and the influence of front wheel trail are included but secondary coupling effects are ignored so as to keep the model tractable. The model is used in this paper to understand the influence of vehicle tilt on the steering angle required for cornering, the desired tilt angle for any specified cornering maneuver and the influence of gyroscopic moments on transient tilting/cornering maneuvers. A study of the model equations also provides insight into how narrow vehicles can be designed so as to be self-stabilizing.     

Controlled Dispersion and Setting of Cellulose Nanofibril - Carboxymethyl Cellulose Pastes

Cellulose - This work investigated the redispersion and setting behavior of highly loaded (~?18 wt.% solids in water) pastes of cellulose nanofibrils (CNFs) with carboxymethyl cellulose...