What's in super glue?




Super glue, known scientifically as cyanoacrylate adhesive, is a family of strong, fast-acting adhesives with industrial, medical, and household uses. The main ingredient in super glue is a cyanoacrylate monomer, typically ethyl cyanoacrylate or methyl cyanoacrylate.




Cyanoacrylate Monomer: This is the primary ingredient that polymerizes and forms strong bonds quickly upon exposure to moisture, such as the trace amounts on the surfaces being bonded or in the air.


Stabilizers: These are added to prevent the glue from polymerizing inside the bottle. An example of a stabilizer used in super glue is hydroquinone.


Thickeners: To modify the viscosity, thickeners can be added. A high-viscosity glue would be gel-like, allowing it to fill larger gaps between surfaces.


Plasticizers: These are added to some formulations to increase flexibility and reduce brittleness of the set adhesive.




The main chemical reaction involved in the setting of super glue is anionic polymerization. When the monomer comes into contact with a surface, the ionic species present (often from the slight moisture on most surfaces) trigger the polymerization of the monomer molecules into long chains, forming a hard, solid plastic mesh that holds materials together.


Applications and Considerations


Super glue is famed for its strength and speed of bonding. It's used for various tasks, from simple household repairs to medical applications, such as sutureless wound closure. However, its strength and speed can also be a drawback, as it can bond to skin and other unintended surfaces rapidly.


In its liquid form, super glue is usually clear and colorless with a sharp, irritating odor. Users must handle super glue with caution to avoid skin contact and fumes, and it should be stored in a cool, dry place to prevent premature polymerization and prolong its shelf life.




how toxic is it?




Cyanoacrylate adhesives, like super glue, are generally considered to have low toxicity. Here's a breakdown of its toxicity profile:


Acute Toxicity


Skin: Super glue can bond skin instantly. While the bond can typically be removed or will slough off in time as skin naturally exfoliates, the glue itself is not highly toxic to the skin. However, forcible removal can cause skin damage.


Eyes: If super glue enters the eyes, it can cause irritation and injury due to the bonding of the eye tissues. It requires immediate medical attention but typically does not cause permanent damage.


Inhalation: The fumes from cyanoacrylates can irritate the mucous membranes of the respiratory tract. In a well-ventilated area, the risk is minimal, but chronic exposure to high concentrations could lead to more serious respiratory issues.


Ingestion: Swallowing super glue can lead to adhesion of mouth tissues, but it is not highly toxic if ingested in small amounts. Nevertheless, ingestion is a medical emergency due to the risk of bonding internal tissues.


Chronic Toxicity


With proper use, the risk of chronic toxicity from super glue is low. However, industrial workers with long-term exposure to cyanoacrylate vapors may experience respiratory irritation or sensitization.


Environmental Toxicity


Cyanoacrylates are not considered major environmental hazards. They rapidly polymerize and become inert in the environment. However, disposal should be done according to local regulations, as the monomers in their liquid form are more reactive and could pose a risk.


Safety Tips


Use in a well-ventilated area to avoid inhaling fumes.


Wear gloves to prevent skin contact.


Keep away from eyes and mouth.


Follow the manufacturer’s instructions for use and storage.


In summary, while super glue can cause immediate bonding of tissues and irritation due to its adhesive properties, its chemical components are not highly toxic to humans or the environment when used in the small quantities typically found in consumer products. Always seek medical advice if super glue is misused in a way that leads to exposure beyond superficial contact.




What could it react with?




Cyanoacrylate adhesives, such as super glue, can react with a variety of substances and conditions:


Moisture and Water:


Cyanoacrylates react with moisture (water) to initiate polymerization. This is why super glue sets rapidly when it comes into contact with slightly moist surfaces.




Some alcohols can interfere with the setting process or dissolve the polymer to some extent. Isopropyl alcohol can sometimes be used to clean surfaces before applying the glue or to remove it after it has dried.


Acids and Bases:


Strong acids or bases can cause cyanoacrylates to polymerize. In a high-pH environment, the polymer may degrade more rapidly.


Active Metals:


Cyanoacrylates can react with certain metals such as aluminum, copper, and its alloys, which can act as catalysts for the polymerization process, sometimes releasing heat.


Heat and Flames:


Cyanoacrylate adhesives decompose at high temperatures, potentially releasing irritating fumes such as formaldehyde.


Forcible Separation:


While this is not a chemical reaction, trying to pull apart objects bonded with cyanoacrylate can sometimes cause the glue to release heat and result in a phenomenon known as an exothermic reaction.


It’s important to note that the polymerization of cyanoacrylates is an exothermic process. When large amounts of glue are used, the heat generated from the reaction can be significant and potentially cause burns or a fire hazard.


For safety reasons, super glue should be kept away from incompatible substances, and it should be used according to the safety guidelines provided by the manufacturer. Proper storage and disposal are also important to prevent unwanted reactions.




What happens when it's put on styrofoam?




Super glue (cyanoacrylate) reacts readily with many substances, especially those that are slightly basic or have active hydrogen atoms which can initiate the polymerization process. Here’s what can happen with different materials:


Water and Moisture


Cyanoacrylate reacts with water to trigger the polymerization process, which is why it sets so rapidly in the presence of humidity or on slightly moist surfaces.


Alcohols and Amines


These can accelerate the polymerization of cyanoacrylate, making it set more quickly.


Cotton or Wool (Cellulose)


Reacting super glue with materials like cotton or wool can cause an exothermic reaction (releasing heat), potentially causing burns or fires with enough quantity and surface area.


Acids and Bases


Strong acids and bases can break down cyanoacrylates over time or prevent them from setting properly.




With plastics, the reactivity can vary widely. For some plastics, cyanoacrylates can act as a solvent, dissolving or deforming the plastic. Others may not react much at all.


When it comes to Styrofoam (polystyrene foam), cyanoacrylate might dissolve or "eat through" the foam. The solvents in the glue can react with the polystyrene, causing it to degrade. This reaction can release potentially harmful fumes and result in a messy dissolution of the foam material. It's generally recommended to use adhesives specifically designed for use with polystyrene when working with Styrofoam.




Which adhesives are intended for styrofoam?




When working with Styrofoam, also known as expanded polystyrene (EPS) or extruded polystyrene (XPS), it’s important to choose adhesives that won’t dissolve or damage the foam. Here are some types of adhesives that are generally suitable for bonding Styrofoam:


Water-Based Adhesives


PVA Glue (Polyvinyl Acetate): Common white glue that is safe for foam. It's not very strong but can be used for light applications.


Acrylic Cement: Designed for plastics, including Styrofoam, it forms strong bonds without damaging the foam.


Hot Glue


Low-Temperature Hot Glue Guns: They can be used carefully, as high temperatures can melt Styrofoam.


Foam-Safe Adhesives


Spray Adhesives: Many brands offer spray adhesives specifically labeled as safe for use with Styrofoam. These create a protective layer that bonds without damaging the foam.


Silicone-based Adhesives: They do not harm the foam and provide a flexible bond.


Epoxy for Polystyrene: Some two-part epoxies are formulated to work with foam materials without causing damage.


Construction Adhesives


Specific Foam Board Adhesives: These are formulated to bond insulation foam boards and panels. They usually come in tubes for use with a caulking gun.


Specialty Adhesives


UHU Por: A specialized glue designed for Styrofoam and similar materials.


3M Foam Fast 74: A spray adhesive made for foam bonding.


It’s important to read the product label to ensure compatibility with Styrofoam, as some adhesives, even if they are suitable for other types of foam, may contain solvents that will degrade polystyrene foams. Always test the adhesive on a small, inconspicuous area first to check for any adverse reaction.




What type of glue would be good to combine with portland cement or gypsum to form a type of putty? PVA?




When combining adhesives with Portland cement or gypsum to create a putty or paste for construction purposes, you're generally looking for an additive that can provide enhanced bonding properties, increase flexibility, and possibly impart water resistance to the final mixture.


For Portland Cement


PVA (Polyvinyl Acetate): It's commonly used as a primer or additive in cementitious mixtures to improve adhesion and reduce the brittleness of the dried cement. PVA, when added to Portland cement, forms a tenacious bond to porous surfaces and can be used as a fortifying additive in mortar and concrete.


Acrylic Polymer Emulsions: These are often more suitable than PVA for outdoor applications because they are more resistant to UV light and weathering. They can improve flexibility and adhesion in the cement mix.


SBR (Styrene-Butadiene Rubber) Latex: It is another polymer that can be mixed with cement to improve its sticking properties and make the resulting mix more durable and less permeable.


For Gypsum


PVA: Just like with cement, PVA can be used with gypsum to improve its adhesive properties and reduce brittleness. It can be mixed with gypsum products to improve their flexibility and to create a stronger bond with the substrates.


Cellulose Ethers: These can be used to control the water retention and consistency of gypsum-based products, improving workability and adhesion.


Acrylic and Vinyl Acetate Copolymers: These can be added to gypsum to enhance its performance characteristics, such as toughness and flexibility.




The exact proportions and type of glue or additive can depend on the specific application and requirements, such as flexibility, cure time, and environmental exposure.


When using PVA or any other additive, it's important to check compatibility with the cement or gypsum product, as well as the intended application, since different products are formulated for specific uses.


Safety is also a concern. Ensure that proper protective equipment is used when handling these materials, and follow all safety data sheet (SDS) instructions.


It's always recommended to follow the manufacturer's guidelines or consult a professional for the correct additive to use for your specific project.




In the Rennaisance, they used Rabbit's Glue to make paint. What's the compound composed of?




During the Renaissance, rabbit skin glue, also known as "rabbit glue" or simply "size," was commonly used as a binder in paint and as an adhesive. The compound is made from collagen derived from the skin, bones, and connective tissues of rabbits. Here’s more about its composition and usage:




Collagen: The primary component of rabbit skin glue is collagen, a protein that, when heated with water, forms a gelatinous substance. Once cooled, it solidifies into a transparent and somewhat brittle solid.


Water: To activate the adhesive properties of rabbit skin glue, it is mixed with water and heated until it forms a warm liquid gel.




Adhesive Quality: When it dries, rabbit skin glue provides a strong yet reversible bond. Its ability to be reactivated with heat and moisture made it valuable in art restoration and repair.


Hygroscopic Nature: It can absorb and release moisture, which means it can expand and contract with changes in humidity. This can be both a benefit and a drawback in artworks.




As a Binder: Rabbit skin glue was used as a binder in gesso, a white paint mixture that was often used to prepare wooden panels and canvases for painting.


In Paints: Artists would mix it with pigments to create tempera paint, providing a durable yet flexible paint film.


In Art Conservation: Due to its reversible nature, it was (and still is) used in art conservation.


The use of rabbit skin glue has declined due to the development of synthetic adhesives and binders that offer greater stability and resistance to changes in humidity and temperature. However, it is still used today in some traditional art and restoration practices due to its unique properties.




What are the modern day alternartives?




Modern alternatives to rabbit skin glue are varied and often tailored to specific applications in art and conservation, offering improved stability, longevity, and ease of use. Some of these alternatives include:


For Paint and Art Conservation


Acrylic Polymers: Acrylic dispersions are widely used as binders for paints, offering flexibility, durability, and excellent aging characteristics. They are also reversible under certain conditions, which is essential for conservation work.


PVA Emulsions: Polyvinyl acetate emulsions are used as adhesives and sizing agents. They are pH neutral and less hygroscopic than rabbit skin glue, which means they are less prone to damage from changes in humidity.


Aliphatic Resins: These are also used as adhesives in woodworking and for sizing canvas in place of traditional animal glues. They tend to be more flexible and have better aging properties.


Gelatin: A refined form of collagen, similar to rabbit skin glue but often derived from bovine sources, is still used in conservation and artistic applications due to its reversibility and lower hygroscopic nature.


Cellulose Ethers: Substances like methylcellulose and carboxymethylcellulose are used in conservation for their adhesive properties and reversible nature, as well as for their stability and resistance to biological degradation.


For Canvas Sizing


Gesso: Modern gesso is a mixture of a white pigment such as calcium carbonate with an acrylic polymer medium. It provides a stable, non-absorbent substrate for painting.


Conservation-Grade Adhesives: Conservators use various synthetic resins that can be tailored to the specific needs of the artwork and the materials involved, ensuring compatibility and reversibility.


In Woodworking and General Adhesives


Epoxy Resins: These provide a very strong and durable bond for woodworking and other crafts.


Cyanoacrylates: Commonly known as super glues, these provide quick-setting and strong adhesion for a variety of materials.


Urea-Formaldehyde Resins: These are used in pressed wood products and as adhesives in woodworking.


These modern materials are formulated to maintain the fine balance between adhesion, flexibility, and reversibility while offering improved resistance to environmental factors and aging. They have been adopted widely due to their predictability, ease of use, and the scientific understanding of their long-term behavior.




What could I use to glue soap together?




Gluing soap together is a bit unconventional since soap's properties can make it difficult for many adhesives to bond effectively. However, there are a few methods you might consider to adhere soap pieces together:


Using More Soap


Melt and Pour: One of the simplest ways to join two pieces of soap is to slightly melt the surfaces that need to be joined and stick them together. You can do this by gently heating the surfaces with a hair dryer or on a warm surface and then pressing them together until they cool and fuse.


Glycerin: Applying a small amount of liquid glycerin to the surfaces of the soap pieces before pressing them together can help them adhere. Glycerin is a component of soap that can act as a glue when two pieces are joined and left to set.


Water-Soluble Adhesives


Water-Soluble Paper Glue: If the soap needs to be glued temporarily or if it's more about keeping it in place rather than fusing it, a water-soluble adhesive might work. These will hold the pieces together but will dissolve once the soap is wet.


For Soap Crafting


Clear Melt and Pour Soap Base: If you're crafting with soap and want to add embellishments or join pieces creatively, using a clear melt and pour soap base as an adhesive layer can be an effective solution. Melt a small amount and use it to join pieces, much like using a 'glue' made of soap itself.


Industrial Adhesives


Food-Grade Adhesives: If the soap must remain functional, using a non-toxic, food-grade adhesive may be necessary. These are specially formulated to be safe for use on items that may come into contact with skin or food.


When choosing an adhesive method for soap, consider the purpose of the glued soap (decorative vs. functional), exposure to water, and safety regarding skin contact. For soaps that will be used on the body, it's essential to ensure that all materials used are skin-safe and non-toxic.




What are some possible homemade DIY glue recipes? (e.g. acetone and plexiglass) Also, how safe are they to use?




Creating homemade DIY glue can be a fun and practical project. Here are a few recipes using readily available materials. It's crucial to consider safety, especially regarding fumes, skin contact, and the flammability of some ingredients.


1. Flour and Water Paste


Ingredients: Flour, water, and a bit of salt to prevent mold.


Method: Mix 1 part flour with 1 part water until you get a paste consistency. Add a pinch of salt. This glue is excellent for paper crafts.


Safety: Very safe, non-toxic, and commonly used for children's projects.


2. Cornstarch Glue


Ingredients: Cornstarch, water.


Method: Mix 1 part cornstarch with 4 parts cold water. Heat over medium heat until the mixture thickens. It can be used as a paper glue or a thickening agent.


Safety: Non-toxic and safe for general use.


3. Milk and Vinegar Casein Glue


Ingredients: Milk, white vinegar, baking soda.


Method: Warm the milk and add vinegar to curdle it. Filter out the curds, mix with a small amount of water and baking soda to neutralize the acid and achieve the desired consistency.


Safety: Non-toxic, but may have a slight odor due to the vinegar.


4. PVA (Polyvinyl Acetate) Homemade Glue


Ingredients: PVA powder, water.


Method: Dissolve PVA powder in water according to the product instructions. This makes a strong, multipurpose glue.


Safety: Generally safe but follow the safety instructions for the PVA powder, and ensure good ventilation.


5. Acetone and Plexiglass (Acrylic Cement)


Ingredients: Acetone, plexiglass or acrylic scraps.


Method: Dissolve pieces of plexiglass in acetone until a syrupy solution is formed. This can be used to bond acrylic materials.


Safety: Acetone is flammable and emits strong fumes. Use in a well-ventilated area and avoid skin contact. Not recommended for children.


Safety Considerations


Ventilation: Always work in a well-ventilated area, especially when using substances like acetone.


Protective Gear: Wear gloves, goggles, and masks as necessary, especially with chemicals that emit fumes or can irritate the skin.


Flammability: Be cautious with flammable materials. Keep them away from open flames and heat sources.


Skin Contact: Avoid adhesives that can cause skin irritation or allergic reactions. Wash skin immediately if contact occurs.


Ingestion and Inhalation: Keep DIY glues away from food and drinks. Do not ingest any homemade glue, and avoid inhaling fumes.


When making and using DIY glues, consider the application and choose ingredients accordingly, ensuring the safety and suitability of the adhesive for the intended use.




What other aspects of glue are worth exploring?




Exploring the world of adhesives reveals a fascinating intersection of chemistry, physics, and practical applications. Here are several aspects worth delving into:


1. Adhesive Mechanisms


Understanding how different adhesives bond at the molecular level is intriguing. The primary mechanisms include mechanical bonding, chemical bonding, and physical adsorption. Exploring these mechanisms helps in selecting the right glue for specific materials and conditions.


2. Curing Processes


The transformation from a liquid or paste to a solid bond varies among adhesives and is crucial for their performance. Some glues cure through evaporation of solvents, others through cooling (like hot melts), and some require chemical reactions triggered by light, moisture, or air.


3. Strength and Durability


Adhesives vary widely in tensile strength, shear strength, and flexibility. The durability of the bond under different environmental conditions such as temperature, humidity, and exposure to chemicals is vital for applications ranging from aerospace to underwater constructions.


4. Types of Adhesives


Exploring the vast array of adhesives, from natural glues like animal-based and plant-based adhesives to synthetic ones like epoxies, silicones, and cyanoacrylates, reveals a world of innovation tailored to specific applications.


5. Environmental Impact


The sustainability of adhesives, including their lifecycle, biodegradability, and the environmental impact of their production and disposal, is a growing field of study. Eco-friendly alternatives are increasingly sought after in response to environmental concerns.


6. Health and Safety


The health risks associated with the use of certain adhesives, especially solvent-based and toxic ones, are significant. Research into non-toxic, safe alternatives is crucial, especially for applications in homes, schools, and food packaging.


7. Innovative Applications


Adhesives play a critical role in innovative technologies, such as medical adhesives used for wound care and surgical applications, and in the electronics industry for components assembly. The development of conductive glues opens new avenues in electronics and materials science.


8. Historical and Cultural Aspects


The history of glue is as old as human civilization, with evidence of natural adhesives used thousands of years ago. Understanding the evolution of adhesives and their role in cultural artifacts and historical constructions offers insights into human ingenuity and resourcefulness.


9. Testing and Standards


The methodologies for testing adhesive properties, such as peel strength, shear strength, and fatigue resistance, are critical for ensuring reliability and safety in their applications. Standards set by organizations like ASTM and ISO help in benchmarking and quality control.


10. Future of Adhesives


Research into smart adhesives that can respond to environmental stimuli, self-healing glues, and reversible adhesives points to a future where adhesives not only bond materials but also add functionality to the bonded system.


Exploring these aspects provides a deeper appreciation of the science and technology behind adhesives and their integral role in modern society.




Make a chart using these criteria and evaluate the different adhesives we discussed.




Certainly, here's a text-based table evaluating the various compounds related to glues and adhesives that we've discussed:





Ease of Use

Environmental Impact

Flour and Water Paste






Cornstarch Glue






Milk and Vinegar Casein Glue






PVA (Polyvinyl Acetate)






Acrylic Polymers






Acetone and Plexiglass

Very High





Cyanoacrylates (Super Glue)

Very High





Epoxy Resins

Very High

Very High




SBR (Styrene-Butadiene Rubber)






Gelatin (from Rabbit Glue)







  • Strength: Refers to the adhesive's ability to withstand force without separating.

  • Durability: Indicates how well the adhesive can maintain its bond over time under various conditions.

  • Safety: Considers the potential health risks associated with the use of the adhesive, including toxicity and flammability.

  • Ease of Use: Reflects how simple and convenient the adhesive is to apply and work with.

  • Environmental Impact: Takes into account the adhesive's biodegradability, the sustainability of its production, and its overall environmental footprint.

This table provides a general overview, but it's important to consider the specific application and conditions when choosing an adhesive, as performance can vary greatly depending on the use case.


Flour and Water Paste and Cornstarch Glue score high on safety, environmental impact, and ease of use but low on strength and durability, making them suitable for light, non-permanent applications.


Milk and Vinegar Casein Glue offers a moderate balance across the board, with slightly lower ratings in ease of use due to the preparation process.


PVA and Acrylic Polymers stand out for their strength, durability, and relatively good safety and environmental profiles, making them versatile for more demanding applications.


Acetone and Plexiglass scores high in strength and durability but lower in safety, ease of use, and environmental impact, indicating it's more specialized and requires careful handling.


This chart helps visualize the trade-offs and considerations when choosing an adhesive for specific applications.