With PDFreactor, you have full control over the page break behavior via the CSS "break-*" properties. So to force a page break, you could use the following style:

/* Inserts a page break after the element */
.break-after {
    break-after: page;
/* Inserts a page break before the element */
.break-before {
    break-before: page;

For more information about pagination or layout in general, please refer to the PDFreactor manual here or have a look at the attached sample (HTML source file as well as the resulting PDF).