HQEE is the premier diol chain extender for MDI-based polyurethane elastomers. Compared to 1,4-butanediol, the workhorse of the industry, HQEE-MDI based polyurethanes exhibit a higher hard-block melt temperature, superior tensile properties, split-tear resistance, hardness and rigidity, resiliency, low hysteresis, and enhanced thermal aging performance.
HQEE is the premier diol chain extender for MDI-based polyurethane elastomers. Compared to 1,4-butanediol, the workhorse of the industry, HQEE-MDI based polyurethanes exhibit a higher hard-block melt temperature, superior tensile properties, split-tear resistance, hardness and rigidity, resiliency, low hysteresis, and enhanced thermal aging performance.
Let's take a look at five useful facts about Gantrade's high-purity HQEE as a chain extender in polyurethane elastomers. As a leader in the global distribution of HQEE, we pride ourselves on providing our customers with the latest information to help them select the right chemical products for their product specifications.
1. Performance attributes of HQEE MDI-based polyurethane elastomers
When it comes to performance in extreme environments, HQEE is the chain extender of choice for most formulators. As a chain extender, HQEE reacts with MDI and MDI prepolymers to create crystalline "hard-segment" domains that efficiently microphase separate. Many studies have shown that the properties of a polyurethane are highly dependent on the characteristics and perfection of this hard-block phase.
HQEE-MDI really stands out from the competition with regard to achieving the following specific product attributes:
Superior elevated temperature and heat-aging properties
Hardness and rigidity
Low heat buildup or hysteresis under dynamic flex conditions
Excellent resiliency and rebound characteristics
Tear strength and split-tear resistance
Enhanced low-temperature flex strength due to effective microphase separation
Under elevated temperature conditions, HQEE MDI elastomers are the preferred system
The melting temperatures of the HQEE-MDI hard domain are elevated in polyurethane elastomers versus polyurethanes that are chain-extended with other diols. Based on DSC results, HQEE extension produces a 30 °C higher hard-segment melting temperature and a higher melt enthalpy (the degree of heat required to melt the hard segment) indicating superior elevated temperature properties of HQEE-MDI compared to BDO-MDI elastomers.
HQEE-based systems show greater phase segregation and a higher order of hydrogen bonding in the hard domain of polyurethanes. The rigid aromatic structure promotes hard segment packing and the symmetrical -OCH2CH2-segment in HQEE enables intermolecular hydrogen bonding with urethane linkages. These aggregate forces effectively facilitate hard-segment packing, leading to well defined microphase separation morphologies in the polyurethane.