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Polyhexamethylene guanidine (PHMG) is a polymeric guanidine-based disinfectant and antimicrobial agent used in a variety of industrial and healthcare settings.
CAS Numbers
32289-58-0
Synonyms
PHMG,Poly(hexamethylene guanidine),Polyhexamethylene guanidine hydrochloride (PHMG-HCl),Polyhexamethylene guanidine phosphate (PHMG-P),Polyguanidine,Poly(hexamethyleneguanidine), Poly(hexamethyleneguanidinium)
Introduction
Definition and General Overview
Polyhexamethylene guanidine (PHMG) is a polymeric guanidine derivative characterized by repeating units of hexamethylene chains linked with guanidine functional groups.
It is a cationic polymer notable for its potent antimicrobial properties and wide-ranging industrial and medical applications.
Historical Development and Discovery
First synthesized in the 1950s-1960s as part of the search for novel disinfectants and antiseptics.
Early studies focused on guanidine derivatives for antimicrobial activity.
Commercial interest surged with the development of PHMG-based biocides.
Recent decades have seen growing concerns regarding safety, prompting more research.
Importance and Relevance
PHMG's effectiveness against a broad spectrum of microorganisms, including bacteria, fungi, and viruses, makes it critical in healthcare, water treatment, and hygiene.
Its polymeric nature provides enhanced stability and efficacy compared to small molecule guanidines.
Increasing global demand for safer, more efficient disinfectants fuels PHMG research.
Chemical Structure and Properties
Molecular Formula and Weight
General formula: (C_7H_17N_3)_n where n indicates the degree of polymerization.
Molecular weight varies widely due to polymer length (from thousands to hundreds of thousands Daltons).
Chemical Structure and Functional Groups
Consists of hexamethylene chains (-CH2- units) linked via guanidine groups (-C(=NH)-NH2).
Guanidine moiety imparts strong basicity and positive charge under physiological pH.
The polymer is linear or slightly branched depending on synthesis.
Physical Properties
Appearance: Typically a white to off-white powder or granular solid.
Solubility: Highly soluble in water due to cationic nature; forms clear aqueous solutions.
Thermal stability: Stable up to ~250°C but degrades on prolonged heating.
pH behavior: Strongly basic polymer, typically forming salts (e.g., hydrochloride).
Chemical Behavior and Reactivity
Cationic polymer with strong affinity for negatively charged surfaces (like microbial membranes).
Reacts with anionic species to form complexes.
Stable under neutral and mildly acidic conditions, decomposes in strong acids/bases.
Synthesis and Production Methods
Industrial Production
Polymerization of hexamethylenediamine with cyanamide or guanidine salts.
Conditions: Typically carried out in aqueous medium under controlled temperature and pH.
Catalysts and stabilizers may be employed to optimize polymer length and purity.
Laboratory Synthesis
Stepwise condensation polymerization.
Alternative methods involve ring-opening polymerization or use of guanidine derivatives.
Raw Materials and Reagents
Hexamethylenediamine: Primary raw material, often sourced from petrochemical processes.
Guanidine derivatives: Cyanamide, guanidine carbonate, hydrochloride, etc.
Catalysts such as acids or bases to control reaction rate.
Process Parameters Affecting Quality
Temperature, pH, reaction time.
Ratio of monomers influences molecular weight.
Purification steps (dialysis, precipitation) critical to remove residual monomers and byproducts.
Mechanism of Action
Antimicrobial Mechanism
Cationic PHMG binds to negatively charged microbial membranes.
Disrupts membrane integrity, causing leakage of cellular contents.
Interferes with essential metabolic processes inside cells.
Interaction with Microbial Membranes
Electrostatic interaction with phospholipids.
Insertion of hydrophobic segments into lipid bilayer destabilizes membrane.
Leads to cell lysis and death.
Spectrum of Activity
Effective against Gram-positive and Gram-negative bacteria.
Fungicidal activity against yeasts and molds.
Virucidal action against enveloped viruses.
Applications of PHMG
Use as Disinfectant and Biocide
Used in hospitals, food processing, and public sanitation.
Active ingredient in sprays, wipes, and surface disinfectants.
Water Treatment
Controls bacterial growth in industrial water systems, cooling towers, and drinking water.
Prevents biofilm formation.
Medical and Hygiene Products
Incorporated into wound dressings, antiseptic creams.
Used in formulations for personal hygiene (hand sanitizers).
Industrial Uses
Textile industry: as antimicrobial finishing agent.
Paper industry: inhibits microbial degradation.
Coatings and paints: antimicrobial additives.
Agricultural Applications
Seed coatings, crop protection formulations.
SAFETY INFORMATION ABOUT POLYHEXAMETHYLENE GUANIDINE
First aid measures:
Description of first aid measures:
General advice:
Consult a physician.
Show this safety data sheet to the doctor in attendance.
Move out of dangerous area:
If inhaled:
If breathed in, move person into fresh air.
If not breathing, give artificial respiration.
Consult a physician.
In case of skin contact:
Take off contaminated clothing and shoes immediately.
Wash off with soap and plenty of water.
Consult a physician.
In case of eye contact:
Rinse thoroughly with plenty of water for at least 15 minutes and consult a physician.
Continue rinsing eyes during transport to hospital.
If swallowed:
Do NOT induce vomiting.
Never give anything by mouth to an unconscious person.
Rinse mouth with water.
Consult a physician.
Firefighting measures:
Extinguishing media:
Suitable extinguishing media:
Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Special hazards arising from the substance or mixture
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas
Advice for firefighters:
Wear self-contained breathing apparatus for firefighting if necessary.
Accidental release measures:
Personal precautions, protective equipment and emergency procedures
Use personal protective equipment.
Avoid breathing vapours, mist or gas.
Evacuate personnel to safe areas.
Environmental precautions:
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Methods and materials for containment and cleaning up:
Soak up with inert absorbent material and dispose of as hazardous waste.
Keep in suitable, closed containers for disposal.
Handling and storage:
Precautions for safe handling:
Avoid inhalation of vapour or mist.
Conditions for safe storage, including any incompatibilities:
Keep container tightly closed in a dry and well-ventilated place.
Containers which are opened must be carefully resealed and kept upright to prevent leakage.
Storage class (TRGS 510): 8A: Combustible, corrosive hazardous materials
Exposure controls/personal protection:
Control parameters:
Components with workplace control parameters
Contains no substances with occupational exposure limit values.
Exposure controls:
Appropriate engineering controls:
Handle in accordance with good industrial hygiene and safety practice.
Wash hands before breaks and at the end of workday.
Personal protective equipment:
Eye/face protection:
Tightly fitting safety goggles.
Faceshield (8-inch minimum).
Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Skin protection:
Handle with gloves.
Gloves must be inspected prior to use.
Use proper glove
removal technique (without touching glove's outer surface) to avoid skin contact with this product.
Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices.
Wash and dry hands.
Full contact:
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
Splash contact
Material: Nitrile rubber
Minimum layer thickness: 0.11 mm
Break through time: 480 min
Material tested:Dermatril (KCL 740 / Aldrich Z677272, Size M)
It should not be construed as offering an approval for any specific use scenario.
Body Protection:
Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Respiratory protection:
Where risk assessment shows air-purifying respirators are appropriate use a fullface respirator with multi-purpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls.
If the respirator is the sole means of protection, use a full-face supplied air respirator.
Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Control of environmental exposure
Prevent further leakage or spillage if safe to do so.
Do not let product enter drains.
Discharge into the environment must be avoided.
Stability and reactivity:
Chemical stability:
Stable under recommended storage conditions.
Incompatible materials:
Strong oxidizing agents:
Hazardous decomposition products:
Hazardous decomposition products formed under fire conditions.
Carbon oxides, Nitrogen oxides (NOx), Hydrogen chloride gas.
Disposal considerations:
Waste treatment methods:
Product:
Offer surplus and non-recyclable solutions to a licensed disposal company.
Contact a licensed professional waste disposal service to dispose of this material.
Contaminated packaging:
Dispose of as unused product
