When a system undergoes crosslinking, it means that the molecules within the system are forming covalent bonds with each other. This process can affect the solubility of the system in several ways.
1. Insolubility: Crosslinking can lead to a decrease in solubility. When molecules are crosslinked, they form a network structure that restricts the movement of solvent molecules. This makes it more difficult for the solvent to penetrate the network and dissolve the system. As a result, the system becomes less soluble.
2. Gel formation: Crosslinking can also result in the formation of a gel. A gel is a three-dimensional network of crosslinked molecules that traps a large amount of solvent within its structure. Gels have a characteristic rubbery or elastic consistency. The formation of a gel indicates that the system has become insoluble due to crosslinking.
During the process of crosslinking, several observable and physical changes can occur. These changes can be observed in the photopolymerization video you mentioned.
1. Viscosity increase: As crosslinking progresses, the viscosity of the system tends to increase. This is because the crosslinked molecules restrict the flow of the system, making it thicker and more resistant to deformation.
2. Solidification: Crosslinking can cause a liquid system to solidify. As the crosslinks form, the system transitions from a liquid state to a solid state. This solidification is a result of the formation of a network structure that locks the molecules in place.
3. Formation of a three-dimensional structure: Crosslinking creates a three-dimensional network of interconnected molecules. This structure gives the system its unique properties, such as insolubility and gel formation.
It is important to note that the observations and physical changes during crosslinking can vary depending on the specific system and crosslinking method used. The photopolymerization video you mentioned may provide specific examples and visual demonstrations of these changes.
Sources:
- "Polymer Chemistry: The Basic Concepts" by Paul C. Hiemenz and Timothy P. Lodge
- "Introduction to Polymer Chemistry" by Charles E. Carraher Jr.
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