Glass transition temperature dendritic macromolecules

The nature of the chain end groups have also been shown to have a dramatic effect on the glass transition temperature of dendritic macromolecules. A variety of workers have investigated this question by the preparation of chain end... 

Wooley, K.L. Hawker, C.J. Pochan, J.M. Erechet, J.M.J. Physical properties of dendritic macromolecules a study of glass transition temperature. Macromolecules 1993, 26, 1514-1519. 

A comparison of the physical properties of hyperbranched and dendritic macromolecules with linear polymers and the linear analogs of these 3-dimensional polymers is presented. It is found that thermal properties, such as glass transition temperature and degradation, are the same regardless of the macromolecular architecture but are very sensitive to the number and nature of chain end functional groups. However, other properties, such as solubility, melt viscosity, chemicd reactivity, intrinsic viscosity were found to be very dependent on the macromolecular architecture. 

A number of conclusion can be drawn from the above studies. Firstly some physical properties such as glass transition temperature and thermal degradation are independent of macromolecular architecture but are dependent on the nature of the chain ends. Other physical properties such as solubility, chemical reactivity, viscosity, etc. are dependent on macromolecular architecture and definite differences are observed between linear, hyperbranched and dendritic macromolecules based on the same building block. 

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