The van Krevelen group contribution method is used to predict the thermo-physical properties of polymers on the basis of the individual structural groups. Use this window to specify which van Krevelen structural groups make up a polymer segment. Polymer components are defined in terms of these polymer segments.
Usage
In the Polymer Segments table on the Definition of Polymer Components Window, enter a Segment Name and push the Enter Data button for van Krevelen Structures.
Structure Type
Select Main Chain Structures to restrict the structure to only main chain groups. Select All Structures to allow all groups, including those with side chains, to be used.
Category
You must select the required Category of structural groups from the drop-down list. This enters the corresponding group numbers into the Group list and makes the Add Group button available.
Group
When you click on a group in the list, a picture of its Structure is displayed. This allows you to browse the available structures to find the ones that you want.
Add Group
Pressing this button inserts the highlighted Group into the table below. You may also add groups by double-clicking on the number in the Group list.
Table of Groups
This shows the defined structure of the Polymer Segment. The entries are as follows:
Group: The number of the selected structural group. This may be entered directly into the field or selected from the Group list. It is advisable to start with the most complex groups and select more elementary groups only when a suitable complex group cannot be found.
Number: The number of occurrences of this group in the polymer segment.
CH2 Groups: Enter the number of methylene groups which are attached as a side chain to the selected structural group. This is only available when the main chain contains at least one methyl (CH3) group.
Structure: This shows a picture of the selected structural group.
See Editing Tabular Data for further information on tabular data entry.
Related topics
PRO/II Components - General Information