Polymer Blending: PGXpand Mixing Guidelines

Sripath’s PGXpand® is a unique, highly bitumen-compatible, specially engineered polymer. Used for bitumen modification in both the roofing and paving industries, its effectiveness and cost-saving benefits have been tested and proven since 2015.

Incorporating PGXpand into bitumen is an endothermic process, meaning the mixture needs to be heated during the entire blending process to maintain the temperature. Proper blending techniques are outlined below. By following these suggested blending temperatures and guidelines, PGXpand melts easily into the bitumen, resulting in liquid-on-liquid mixing. It is highly dosage efficient, storage stable, and easily mixes into bitumen using low shear mixers and short mixing times.

PGXpand Blending Guide

Manufacturing Plant Blending Guidelines

  • If combining with elastomeric polymers, PGXpand may be added before, during or after the other

polymers. However, incorporating PGXpand BEFORE any other elastomers reduces the blend viscosity,

which may aid in the compatibilization of the elastomers into the bitumen.

  • PGXpand is non-abrasive to any components of the shear mill.
  • PGXpand does not impact the slip resistance in the shear mill.

Laboratory Blending Guidelines

Step 1: Preheat the Bitumen:

  • Preheat about 1000g of the binder in a container to 145° C (300° F) in an oven for 30 minutes.

Step 2: Initial Set Up and Pre-Stirring:

  • Place the preheated container of binder on the hot plate and place a thermocouple in the binder such that the tip is about 1/3 of the way down and near the edge of the container.
  • Set the temperature to 163° C (325° F) and wait for the temperature to stabilize.
  • Next, lower the dispersing element into the binder, such that it is 2.5 cm (1 inch) above the bottom of the container.
  • Turn the motor on, set the speed to 600 rpm, and wait for the temperature to stabilize.

Step 3: Addition of Polymer and Blending:

  • Once the binder temperature reaches 163° C (325° F), slowly add the PGXpand to the binder.
  • Blend the polymer and the binder for 60 minutes.
  • Maintain the binder at a temperature between 150-163°C (300-325° F) throughout the blending process.
  • At the end of the 60 minutes, transfer the blended bitumen into a container and store for future testing.

Have additional questions on blending PGXpand? Our technical support team is available 24/7 to assist. Contact us directly here.