Butyl Rubber typically contains about 98% polyisobutylene with 2% isoprene distributed randomly in the polymer chain. To achieve high molecular weight, the reaction must be controlled at low temperatures (-90 to -100 degC).The reaction is highly exothermic.utyl Rubber typically contains about 98% polyisobutylene with 2% isoprene distributed randomly in the polymer chain. To achieve high molecular weight, the reaction must be controlled at low temperatures (-90 to -100 degC).
There may be no single cause of bipolar disorder (aka manic depression). Instead, research indicates the causes of bipolar disorder are probably a combination of biochemical, genetic and environmental factors that may trigger and perpetuate the chemical imbalances in the brain.
1 Bipolar II involves less severe manic episodes than bipolar I; however, their depressive episodes are the same. 2  Cyclothymia is a chronic but milder form of bipolar disorder, characterized by episodes of hypomania and depression that last for at least two years.here is no single cause for bipolar disorder. Indeed, like all psychological disorders, bipolar disorder is a complex condition with multiple contributing factors, including: 1  Genetic: Bipolar disorder tends to run in families, so researchers believe there is a genetic predisposition for the disorder.