Research on the Physicochemical Properties and Applications of Polyethylene Glycol (PEG)
1. Overview of Polyethylene Glycol
Polyethylene glycol (PEG) is a polymer formed by the polymerization reaction of ethylene oxide and water, representing a typical class of polyether compounds. As an important chemical raw material, PEG is widely used in various industrial fields such as medicine, cosmetics, textiles, and rubber due to its unique physicochemical properties.
From a physical standpoint, PEG exhibits significant molecular weight-dependent characteristics. When the molecular weight is below 700, it appears as a colorless and odorless viscous liquid; when within the range of 700-900, it presents as semi-solid; above 1000 molecular weight, it transforms into a light white waxy solid or powder. This morphological change is closely related to variations in chain length and crystallinity.
2. Detailed Description of Physicochemical Properties
2.1 Basic Physicochemical Parameters
The chemical formula for polyethylene glycol is HO(CH2CH2O)nH with CAS registration number 25322-68-3. Its boiling point exceeds 250°C with a flash point reaching up to 270°C; density approximately at 1.125g/cm³. The solubility in water shows significant temperature dependence—at room temperature forming clear colorless solutions at concentrations up to 50mg/mL. Notably, PEG demonstrates excellent miscibility performance with polar solvents like water, ethanol, acetone in any proportion but is nearly insoluble in non-polar solvents such as alkanes.
2.2 Stability Characteristics
Under normal storage conditions, PEG exhibits good chemical stability. The ether bonds within its molecular structure are relatively stable at room temperature but may break down under high temperatures (above 300°C). In terms of oxidative stability: higher molecular weights make PEG more susceptible to oxidation from air due to active terminal hydroxyl groups and changes in chain conformation; thus antioxidants like phenol are often added industrially for enhanced stability.
From safety operation perspectives: PEG has low irritancy towards skin and eyes based on experimental data showing only mild reactions upon rabbit skin contact with doses up to500mg/24h . However , wearing protective gloves & goggles during handling remains advisable against accidental exposure ; immediate rinsing with plenty amounts clean water should be done if contact occurs while seeking medical assistance if necessary .
3.Relationship Between Molecular Structure And Performance
**3 .1 Molecular Structural Features ** n n Data regarding PE G's molecu lar structure indicates that its molar refractive index stands at43 .98 ,with molar volume reaching156 .2m³/mol.This information reflects both flexibility & spatial arrangement traits associated w ith molecule chains.Isochor ic compressibility measures413 .6while surface tension reads49 dyne /cm—these physical parameters collectively determine special behaviors exhibited by P EG across interfaces.. n **3 .2 Effect Of Molecular Weight ** n The impact exerted by m olecular weight upon P EG's performances proves particularly pronounced.As m olecular weights increase ,water solubility,vapor pressure,and moisture absorption gradually decline whereas freezing points,densities,& viscosities correspondingly rise.This pattern arises from alterations stemming from increased crystalline structures resulting f rom elongated molecules.Example : viscosity levels recorded for P EG -800 @40 °C hover around30 -100cst whilst those observed fo rP E G -1500 @70 °C sit roughly @60 cst —this discrepancy directly influences choices made concerning their respective industrial applications.. n ###4.Toxicology And Environmental Characteristics n 4 .1 Toxicological Data Assessment Toxicological studies indicate thatPE G falls under mildly toxic substances category.Rats subjected intravenously yielded LD50 figures approximating22 g/kg suggesting lower acute toxicity.Chronic toxicity experiments revealed no discernible harmful effects after canines were fed diets containing varying degrees(around % )of different m olecular weights over one year especially noteworthy being how effectively PE G dissolves phenolic compounds making it viable agents dealing w ith pollutants originating therefrom... N 4 .2 Ecological Impact Analysis: Environmental assessments reveal minimal impacts posed byPEG onto aquatic ecosystems owing largely because they’re difficult absorbable through gastrointestinal tracts reducing risks pertaining bioaccumulation.Laboratory findings indicated slight irritation resulted when exposing rabbits’ eyes using5% concentration aqueous solution.Yet despite this cautionary notes surrounding compliance environmental regulations remain paramount ensuring no cumulative adverse consequences arise throughout discharge processes .. ###5.Manufacturing Processes And Technologies ##5 #Main Synthesis Routes Industrial production methods primarily consist three routes: firstly involving ethylene glycol reacting alongside epichlorohydrin catalytically induced second route focusing solely self-polymerizing epichlorohydrin via aluminum-isopropanol catalysts lastly employing120# gasoline solvent aided utilizing aluminum catalyst yielding higher quality products obtained through precise control mechanisms regulating both reaction temperatures(10°to40°)and durations(totaling7 hours). N ##5 #Post-processing Techniques Following completion steps including distillation removing residual solvents,cooling crystallizations followed vacuum drying ensure final product integrity.Control aspects hinge upon managing distributions relating back again specifically impacting end-use qualities.Modern manufacturing practices increasingly adopt advanced techniques suchas fractional distillation aimed elevating purity standards attained therein...##6.Application Areas In-depth Analysis##6 #Low-Molecular Weight Application Series(Peg200): Known exemplary heat transfer capabilities widely utilized thermal carriers capable operating elevated ranges applicable everyday hygiene items serving moisturizers preventing moisture loss further enhancing formulations due ionic salt solubilization roles played textile industries achieving anti-static functionalities improving fabric feel attributes among others....##6 #Medium-Molecular Weight Application Series(Peg400-to800): Particularly valuable medicinal purposes owing biocompatibilities rendering ideal bases ointments suppositories amongst other dosage forms.In metalworking sectors,Peg600 significantly enhances treatment quality surfaces achieved forming lubricious films proving critical precision parts processing tasks accomplished efficiently ...##6 #High-Molecular Weight Application Series(Mw>1000): Exhibiting distinctive rheological properties.PEG1500 serves dispersants markedly stabilizing pigment dispersion rates typically controlled between10%-30%.Rubber industry exploits lubrication features minimizing energy consumption extending lifespan products notably worth mentioning includes utilization Peg4000 series paper-making processes functioning dual purpose enhancing glossiness smoothness alike…###7.Storage Management Optimization Strategies ##7 Storage Conditions Optimization :Storage conditions must maintain cool dry environments strictly sealed avoiding humidity issues.Liquid variants best stored stainless steel glass containers preventing metallic ions catalyzing oxidation phenomena.Meanwhile attention directed towards keeping moisture-sensitive grades(molecul arweights<2000)especially safeguarded against dampness infiltrations..#8 Sterilization Treatment Protocols:#Peg aqueous solutions employ either pressurized heating(121℃),filtration sterilizations γ-ray irradiation protocols care taken not exceed150℃for solid-state treatments lest risk compromising structural integrity degradation occurring hence proper selections become crucial given significance attached pharmaceutical-grade outputs produced thereby!#9 Recent Advances Future Prospects Over recent years breakthroughs have emerged surrounding use peg-based technologies aiding drug development efforts linking together peg segments covalently bonded protein therapeutics prolonging half-lives lowering immunogenicity concerns.Biomedical materials field highlights importance hydrogels showcasing tunable mechanical properties exhibiting compatibility thus emerging key candidates tissue engineering domains.Forthcoming inquiries shall focus developing functionalized derivatives expanding applicability realms targeting delivery systems smart materials cutting-edge frontiers...