Engineering Research Equipment Grant: A High Pressure Thermogravimetric System for Various Equilibrium, Transport and Reaction Studies

这笔赠款中提供的设备是一种特殊的热重系统，由卡恩C-1100型压力天平以及相关的加压、温度控制和数据采集设备组成。在700摄氏度和140大气压下进行测量将是可能的，这代表着远远超出了传统热重方法所能达到的条件。凭借这种独特的能力，高温含氟聚合物和先进热塑性塑料的特征扩散和气体溶解度数据将成为可能。目前，这样的数据是不存在的，这些性质只能通过对低压数据的外推来估计，这预计会产生重大误差。能够获得这种数据，再加上气泡成核和生长研究，应该会改进聚合物泡沫塑料工艺和产品，使其具有受控的开放和封闭的泡孔结构。在用于数据传输电缆的昂贵的泡沫氟聚合物绝缘的情况下，孔隙率的微小改善将导致显著的材料成本节约和优质产品。此外，SF6、氟里昂123和氟里昂134气体与各种聚合物产生的气体-聚合物相互作用的研究应为评估这些气体作为目前聚合物泡沫工艺中使用的含氯氟利昂的替代品提供基础。后一种气体已被证明对高层大气臭氧层有有害影响，重要的是确定令人满意的替代品。

The equipment provided in this grant is a special thermogravimetric system consisting of a Cahn Model C-1100 Pressure Balance plus associated pressurization, temperature control, and data acquisition equipment. Measurements will be possible at 700 degrees Celsius and 140 atmospheres, which represent conditions significantly beyond those capable with conventional thermogravimetric methods. With this unique capability, characteristic diffusion and gas solubility data will be possible for high temperature fluoropolymers and advanced thermoplastics. Currently, such data are nonexistent and these properties can be estimated only through extrapolation of low pressure data which is expected to produce significant errors. The ability to obtain such data, coupled with bubble nucleation and growth studies, should result in improved polymer foam processes and products with controlled open and closed cellular structures. In the case of costly foamed fluoropolymer insulation for data transmission cable, small improvements in void fraction would result in significant material cost savings and superior products. Also, studies of gas-polymer interactions arising with SF6, Freon 123, and Freon 134 gases with various polymers should provide a basis for evaluating these gases as substitutes for the chlorine-containing freons which are currently used in polymer foam processes. The latter gases have been shown to have deleterious effects on the upper atmosphere ozone layer, and it is important that satisfactory substitutes be identified.