Plasticizer - Plasticizer

An additive is added to a polymeric material to give it flexibility by lowering its melt viscosity, glass transition temperature, elastic modulus, etc. For example, polymeric materials can be plasticized by copolymerizing them with a monomer that has a low glass transition temperature to make the molecular structure flexible (intramolecular plasticization), or by adding a plasticizer. Plasticizing a polymer reduces the cohesive strength of the polymer chains and lowers the glass transition temperature, increasing its flexibility and improving its molding and processing characteristics. The conditions for a plasticizer are:
(1) It is uniformly mixed with polymeric materials (good compatibility).
(2) Colorless, tasteless, odorless, and harmless.
(3) Stable against heat, light, organic solvents, etc.
(4) Not extractable by water, oil, or solvents.
(5) Its melting and boiling points are high and it does not evaporate.
Examples include bis(2-ethylhexyl) phthalate (DOP) and dibutyl phthalate (DBP), which are commonly used as plasticizers for polymer materials. There are also polymers that themselves act as plasticizers. Polymers with a molecular weight of 1000 or more have low volatility and good resistance to extraction, so polyesters with a molecular weight of approximately 1000 to 8000 are used in combination with low molecular weight plasticizers.

Source: Morikita Publishing "Chemical Dictionary (2nd Edition)" Information about the Chemical Dictionary 2nd Edition

高分子材料の溶融粘度，ガラス転移温度，弾性率などを低下させて，材料に柔軟性を与えるために加えるもの．たとえば，高分子材料を可塑化するには，ガラス転移温度の低い単量体と共重合させて分子構造を柔軟(分子内可塑化)にするか，可塑剤を加える方法がある．高分子を可塑化すると，高分子鎖の凝集力の低下，ガラス転移温度の低下などが起こり，柔軟性が増加して成形加工特性が向上する．可塑剤としての条件は，
(1)高分子材料と均一に混和する(相溶性がよい)，
(2)無色，無味，無臭，無害である，
(3)熱，光，有機溶媒などに安定である，
(4)水，油，溶剤により抽出されない，
(5)融点，沸点が高く蒸発しない，
ことなどがあげられる．高分子材料の可塑剤として，フタル酸ビス(2-エチルヘキシル)(DOP)やフタル酸ジブチル(DBP)などがよく利用されている．また，高分子自身が可塑剤となるものがある．分子量が1000以上の高分子は揮発性が低く，耐抽出性がよいことから，分子量約1000～8000のポリエステルが低分子可塑剤と併用されている．

出典　森北出版「化学辞典（第2版）」化学辞典 第2版について　情報