In polymer chemistry, it is often said that obtaining a polymer with certain desired physical properties is often more a problem of engineering than of chemistry. Why is this the case?
Many polymers can be synthesized in the lab, but to produce commercial quantities requires special engineering considerations. That is, what typically works in the lab doesn't always work in the scaled up version.
In polymer chemistry, obtaining a polymer with desired physical properties can be seen as more of an engineering problem rather than a purely chemical one due to several reasons:
1. Structure-Property Relationships: Polymers possess complex structures composed of repeating units, which can vary in terms of length, branching, and composition. The physical properties of a polymer are strongly influenced by its molecular structure. Therefore, achieving specific physical properties requires a precise control over the polymer's structure, which can be challenging from a chemical perspective. Engineering techniques such as manipulating reaction conditions, catalysts, and polymerization techniques are often employed to control the structure of the polymer.
2. Processing Techniques: Even if a polymer with the desired structure is synthesized, its physical properties can be significantly influenced by the processing techniques used during fabrication. Factors such as temperature, pressure, and shear forces can affect properties like mechanical strength, flexibility, and thermal stability. Thus, engineering expertise is required to design appropriate processing methods that can optimize the desired properties of the polymer.
3. Scale-up and Manufacturing: Moving from lab-scale synthesis to large-scale production presents its own set of challenges. The physical properties of polymers can be sensitive to factors like reaction kinetics, heat transfer, and mixing efficiency, which can vary greatly when operating on a larger scale. Engineering principles are essential to design and optimize the manufacturing processes, ensuring consistency and reproducibility of the desired properties.
4. Application-Specific Requirements: The physical properties of a polymer are often tailored to meet specific application requirements. Each application may demand different sets of properties, such as mechanical strength, chemical resistance, optical clarity, or conductivity. Achieving the desired properties necessitates an understanding of the application needs and the ability to engineer the polymer formulation accordingly.
In summary, while chemistry plays a fundamental role in synthesizing polymers, achieving desired physical properties involves applying engineering principles to control the polymer's molecular structure, optimize processing techniques, facilitate scale-up, and meet application-specific requirements. It is this interdisciplinary approach that makes obtaining polymers with desired physical properties more of an engineering challenge.