Maleic Anhydride Grafted Polymers (PP-g-MAH, PE-g-MAH, POE-g-MAH, SEBS-g-MAH): 4 Backbones, Dosage and Selection

Maleic anhydride grafted polymers are polyolefins and elastomers that carry about 0.5 to 1.5 % grafted succinic-anhydride groups, which give a non-polar backbone a reactive polar handle for polyamides, glass, talc and wood. Four backbones carry that handle in commercial compounds, and each one is chosen for a different partner, so the question that decides a formulation is which backbone belongs in which blend.

Maleated polyolefins (compatibiliser is the UK spelling) sit in two families at once among plastic additives: they are compatibilizers between two immiscible polymers and coupling agents between a polymer and a mineral or natural surface, often sold under a single trade name for both jobs.

This page covers how the anhydride is grafted onto a polyolefin and how much of it a commercial grade carries, how the reactive anhydride bonds to polyamide, glass, talc and wood, the 4 backbones used across compounding, PP-g-MAH, PE-g-MAH, POE-g-MAH and EPDM-g-MAH, and SEBS-g-MAH, which backbone and dosage suit which blend or composite, how maleated grades behave in compounding and are affected by moisture, which EU and US rules apply to them, and which producers supply them.

Key figures

• 0.5-1.5 % typical grafted MAH content in commercial maleated polyolefins
• 4 commercial backbones: PP-g-MAH, PE-g-MAH, POE-g-MAH/EPDM-g-MAH, SEBS-g-MAH
• 2-10 wt% typical loading as a compatibilizer; 1-5 wt% as a coupling agent
• SML(T) 30 mg/kg expressed as maleic acid for the monomer, maleic anhydride FCM 234, under EU Regulation (EU) No 10/2011

What Is a Maleic Anhydride Grafted Polymer?#

A maleic anhydride grafted polymer is a commodity polymer, usually polypropylene, polyethylene, an olefin elastomer or SEBS, onto whose chains succinic-anhydride rings have been attached by radical grafting, so that the finished pellet behaves like the base resin in the melt and like a reactive polar molecule at an interface. The grafted product keeps its own identity: PP-g-MAH carries CAS 25722-45-6, and it is a different substance from the monomer used to make it, maleic anhydride, CAS 108-31-6, EC 203-571-6. In use, the grafted anhydride reacts with hydroxyl and amine groups on the other side of an interface while the polyolefin backbone entangles and co-crystallizes with the surrounding matrix, so a reaction that took a fraction of a second at the interface ends up carrying mechanical load across the whole part.

How is maleic anhydride grafted onto a polyolefin?#

Maleic anhydride is grafted onto a polyolefin by peroxide-initiated radical grafting in reactive extrusion at 180 to 190 °C, where peroxide radicals abstract hydrogen from the polymer chain and the anhydride adds to the resulting macroradical. The grafting reaction runs in 4 steps.

1. Peroxide decomposes thermally inside the extruder barrel at 180-190 °C, generating free radicals.
2. Radicals abstract a hydrogen atom from the polyolefin backbone, leaving a reactive macroradical on the chain.
3. Maleic anhydride adds to that macroradical, attaching a succinic-anhydride ring to the polymer chain; the anhydride does not homopolymerize under these conditions.
4. The grafted chain is stabilized and pelletized while a competing side reaction, beta-scission of the polypropylene backbone, cuts some chains at the same time and intensifies as the peroxide level rises.

Molar mass falls as the grafted MAH content rises, up to about 1 wt%, and then plateaus, because most of the additional peroxide beyond that point drives more chain scission rather than more grafting.

Why does grafting raise the melt flow rate of polypropylene?#

Grafting raises the melt flow rate of polypropylene because beta-scission competes with the grafting reaction: the same peroxide radicals that create grafting sites also cut PP chains, so molar mass falls and melt flow rate rises sharply. The effect is large enough that commercial PP-g-MAH grades have a much higher melt flow rate than the polypropylene resin they are made from. A rising melt flow rate is therefore the direct processing-side signature of the same chain scission that delivers the grafted anhydride.

How much maleic anhydride does a commercial grade carry?#

Commercial maleic anhydride grafted polyolefins carry roughly 0.5 to 1.5 % grafted anhydride, with POLYBOND 3200 specified at 0.8 to 1.2 %, because higher graft levels buy little extra reactivity and cost a great deal of molar mass. Grafted anhydride content is not converted into an acid number or expressed as mg KOH/g on this page, since no such conversion is established in our source library; grade selection instead compares the graft percentage itself, backbone by backbone.

How Do Maleic Anhydride Grafted Polymers Work?#

Maleic anhydride grafted polymers work at an interface: the anhydride ring reacts with amine, hydroxyl or silanol groups on the other side, while the polyolefin backbone entangles and co-crystallizes with the matrix, so stress passes across a boundary that was previously weak. The grafted anhydride reacts with 4 groups depending on the partner.

• Amine end groups of polyamides, forming imide links
• Hydroxyl groups of cellulose and wood flour
• Silanol groups on glass fibre
• Hydroxyl and carboxyl groups of polyesters

Reactive compatibilization: the anhydride and amine reaction#

Reactive compatibilization forms the compatibilizer where it is needed: the grafted anhydride reacts with the amine end groups of polyamide during extrusion, creating an imide link and a graft copolymer that sits at the PA to PP interface instead of being added to it ready-made. Most polymer pairs are immiscible, because the entropy of mixing of two long polymer chains is very small, so an uncompatibilized blend stays a coarse, weak, two-phase system no matter how well it is mixed.

Reactive compatibilization built this way is the industrial standard for 4 polymer pairs: PA/PP, PA/ABS, PC/PBT and PET/PO all rely on a grafted reactive group forming the copolymer in situ during compounding. The full class of compatibilizers, reactive and non-reactive alike, is compared on the family hub, alongside the block-copolymer alternatives covered later on this page.

Coupling: the anhydride reaction with glass, talc and wood#

As a coupling agent, the same grafted anhydride reacts with the silanol groups on glass fibre and the hydroxyl groups of wood flour and cellulose, either by esterification or by hydrogen bonding, and anchors them to a polypropylene matrix that would otherwise only touch them. The polyolefin backbone of the grafted chain still co-crystallizes and entangles with the surrounding PP matrix on the other side of that bond, which is what turns a filler particle sitting loose in the resin into one that carries load with it.

The substrate range for this reaction covers glass, mica, talc, wood and natural fibre. Maleated polyolefins are one of 3 chemistries used for this job; the coupling agents for filled and reinforced plastics hub compares them against silanes, which dominate on siliceous fillers, and titanates, which take over on calcium carbonate and other non-siliceous fillers where silanes perform poorly.

Is a maleated polyolefin a compatibilizer or a coupling agent?#

Both terms describe the same product: a maleated polyolefin is called a compatibilizer when it joins two immiscible polymers and a coupling agent when it joins a polymer to an inorganic or natural surface, and SI Group sells POLYBOND 3200 under the second name while formulators use it under the first. The distinction is one of application, not of chemistry, so the same grade can appear on a purchase order under either name depending on what it is being asked to bond.

What Are the 4 Maleic Anhydride Grafted Backbones?#

The 4 maleic anhydride grafted backbones used in compounding are maleated polypropylene (PP-g-MAH), maleated polyethylene (PE-g-MAH), maleated olefin elastomers (POE-g-MAH and EPDM-g-MAH) and maleated SEBS (SEBS-g-MAH), and PP-g-MAH carries by far the largest volume. They are ordered here by industrial volume, PP first, then PE, then the olefin elastomers, then SEBS, and that order repeats in every table and list below.

Grafted anhydride contents are supplier or patent values; confirm on the current datasheet before specifying a grade.

1. PP-g-MAH (maleated polypropylene, MAPP)#

PP-g-MAH, also written MAPP or PP-g-MA (CAS 25722-45-6), is the highest-volume maleated polyolefin and the default choice whenever the matrix is polypropylene. It is sold as off-white pellets with a density of about 0.91 g/cm³ at 23 °C, and commercial grades such as POLYBOND 3200 carry 0.8 to 1.2 % grafted MAH; POLYBOND 3000, 3150 and 3002 and FUSABOND P613 and P353 cover the rest of the PP-matched range. Full identity, grade and regulatory data for maleic anhydride grafted polypropylene (PP-g-MAH) sit on its own substance page.

PP-g-MAH bonds glass fibre, mica, talc, wood and natural fibre to a polypropylene matrix, and it bonds polypropylene itself to polyamide through the same anhydride-amine reaction described above. Studies test PP-g-MAH at 0.5 to 2 wt% in short-glass-fibre-reinforced PP, the loading range that also appears in the dosage table below.

The performance evidence for PP-g-MAH is strongest in recyclate: at 5 % loading, Polybond grades 3150 and 3002 raised notched and reverse Izod impact strength about threefold in a recycled PP and nylon blend, which is why PP-g-MAH is the grade most often specified for mixed polyolefin and PA recyclate streams.

2. PE-g-MAH (maleated polyethylene, MAPE) and EVA-g-MAH#

PE-g-MAH, also called MAPE, is the polyethylene version of the same chemistry and is used wherever the matrix is LLDPE, HDPE or EVA: in wood-plastic composites, in halogen-free flame-retardant cable compounds filled with aluminium hydroxide, and as the tie resin between polyethylene and a barrier layer. The FUSABOND E-series covers PE, the N-series covers PE copolymers, E226 improves adhesion to non-halogenated fillers in LLDPE, and E205 and E204 are used in wood-plastic composites and general compounding of HDPE; POLYBOND 3029 is the MAH-grafted HDPE grade in the same family. No CAS number for PE-g-MAH is established in our source library, so none is stated here.

Non-halogenated mineral fillers such as aluminium hydroxide (ATH) and magnesium hydroxide (MDH) need a coupling agent to keep mechanical properties at the high loadings flame retardancy requires. A reference halogen-free flame-retardant cable formulation from Huber runs EVA 67 parts, LLDPE 17 parts and ATH 160 parts, with 16 phr of coupling agents in total, split between Fusabond 226D at 8 phr and LOTADER 3210 at 8 phr. Maleic-anhydride-grafted EVA at up to 11 % vinyl acetate and up to 2 % grafted MAH is separately cleared under 21 CFR 177.1350 in the United States, the only explicit MAH-graft listing in that part of the food-contact code.

3. POE-g-MAH and EPDM-g-MAH (maleated olefin elastomers)#

POE-g-MAH and EPDM-g-MAH are maleated olefin elastomers, which means they toughen and compatibilize at the same time: the rubbery ethylene-octene or EPDM phase absorbs impact energy while the grafted anhydride anchors it to polyamide. EPDM on its own is already an effective compatibilizer for PP/PE blends, and its maleated version, EPDM-g-MAH, is used specifically for HDPE/PP and LDPE/PP pairs, where the grafted anhydride goes on to react with the amine end groups of polyamide when PA is the third phase.

The clearest performance evidence for this class comes from a multi-phase blend rather than a simple pair. A 2024 study in the journal Polymers reports that adding 10 wt% POE-g-(MAH-co-St) together with 10 wt% SEBS-g-(MAH-co-St) can raise the impact strength of a PA6/PP/ABS/SEBS blend by 823 % against the uncompatibilized blend. The grafts used in that study carried styrene as a co-monomer alongside the maleic anhydride, so the 823 % figure is not directly transferable to a plain, styrene-free POE-g-MAH grade. The ungrafted versions of these rubbery phases are covered under olefin elastomer impact modifiers, the class POE-g-MAH and EPDM-g-MAH are built from.

4. SEBS-g-MAH (maleated styrenic block copolymer)#

SEBS-g-MAH is a hydrogenated styrenic block copolymer carrying anhydride on its rubber midblock, and it is the backbone of choice when the partner is a polyamide or a polyester and the blend also needs low-temperature toughness. Kraton FG1901, the reference grade, is built on SEBS at 30 % polystyrene content, with the maleic anhydride grafted onto the rubber midblock at about 1 to 2 wt% according to patent literature; the saturated ethylene-butylene midblock is stable to UV and ozone, which SEBS grades without a maleic anhydride graft share.

SEBS-g-MAH works as an efficient impact modifier for nylon and polyesters and as a reactive compatibilizer for PA/PP, PP/PET and PE/PA blends. Kraton's CirKular+ C1000, C1010 and C2000 grades are recorded in our source library as non-reactive SEBS compatibilizers used in polymer-blend recyclate, not as maleated types, so their recyclate performance numbers are not presented here as MAH-graft data.

Which Maleated Polymer Suits Which Blend or Composite?#

The right maleated polymer is the one whose backbone matches the matrix: PP-g-MAH for a polypropylene compound, PE-g-MAH for a polyethylene compound, a maleated elastomer when the blend also needs toughness, and SEBS-g-MAH when the partner is a polyamide or a polyester. The blend pairs in the table below range from polyamide compatibilization to filler coupling, and the same logic extends to a full formulation: the additives for wood-plastic composites package pairs a coupling agent from this page with lubricants, UV stabilizers and biocides chosen for the composite as a whole, not for the coupling agent alone.

Published study and supplier values. The optimum is property-dependent and has to be confirmed in a trial.

Request quotes for maleic anhydride grafted polymers: backbone, graft level, volume, blend pair and country, through the plastic additive supplier finder. Formulators comparing grades before an RFQ can also download the Compatibilizer Selection Matrix by Blend Pair (PDF), available with email, role and company.

PA (nylon) blends with PP and PE#

Polyamide blended with polypropylene is the classic case for a maleated polyolefin, because the anhydride reacts with the amine end groups of nylon during extrusion and builds the PA-g-PP copolymer that holds the two phases together. This is the reason reactive compatibilization is the industrial standard for PA/PP: without it, a nylon-rich or polyolefin-rich phase separates on cooling, and any load transferred across the interface tears the part apart instead of stressing both phases together.

The clearest number for this pair comes from recyclate rather than virgin resin: POLYBOND 3150 and 3002 at 5 % in a recycled PP and nylon blend raised notched and reverse Izod impact strength about threefold. The same reaction underlies most of the formulation guidance collected for additives for nylon (polyamide), which covers PA6, PA66 and the high-temperature grades alongside their own additive packages.

Glass Fiber and Talc-Filled Polypropylene#

Glass-fibre-reinforced polypropylene needs 0.5 to 2 wt% PP-g-MAH, because polypropylene has nothing to bond to the silanol groups on a sized glass filament and the fibre otherwise slides in the matrix instead of carrying load. Talc and mica are coupled by the same PP-g-MAH chemistry, through hydrogen bonding to their surface hydroxyl groups rather than the esterification that dominates on glass.

SI Group markets POLYBOND 3200 specifically as a coupling agent for glass-filled PP, which is the commercial name for exactly the reaction described above. Fibre lengths, loadings and sizing systems that pair with this dosage range are covered under glass fiber reinforced plastics.

Wood-plastic and natural fibre composites#

Wood-plastic composites use a maleated polyolefin at roughly 1 to 5 wt% of the compound, and the optimum depends on which property is being bought: a 2026 study in the journal Materials found 1 wt% MAPP best for flexural strength (a 24.7 % gain) and 3 wt% best for tensile strength, modulus and impact in the same PP, wood flour and glass fibre system. The coupling agent reduces water uptake in the composite as well as raising strength, which matters for outdoor WPC decking and cladding as much as the mechanical numbers do.

A separate composite study using a hybrid cellulose and basalt fibre reinforcement in PP found that 5 wt% MA-g-PP raised tensile strength by 45 %, flexural strength by 97 % and notched Charpy impact strength by 13 % against neat, uncoupled PP. FUSABOND E205 is one of the grades used in this application class. Dosage per wood-flour loading and the full lubricant and UV package for the composite are collected under coupling agents for wood-plastic and natural fibre composites.

Mixed polyolefin and PO/PET recyclate#

Mixed polyolefin recyclate is the fastest-growing use of maleated polymers, because post-consumer PE and PP cannot be separated economically and a compatibilizer converts a weak, coarse blend into a usable compound. The non-maleated options for the same mixed streams, non-reactive block copolymers among them, are compared on compatibilizers for recycled plastics, since not every recyclate compatibilizer is a maleated grade.

PET blended with polyolefin (PET/PO) is one of the standard reactive-compatibilization cases alongside PA/PP, and the same POLYBOND 3150 and 3002 grades used at 5 % in recycled PP and nylon appear again here as the reference data point for polyolefin-rich recyclate. Kraton CirKular+ and ENGAGE recyclate performance figures belong to non-reactive SEBS and POE compatibilizers, not to maleated grades, and are not repeated on this page. Restabilization and odour control, which usually accompany a compatibilizer in a recyclate formulation, are covered in the guide to additives for recycled plastics.

Tie layers in multilayer film#

Tie layers in multilayer film are maleated polyethylene: the anhydride bonds the polyolefin layers to EVOH or polyamide, which no polyethylene does on its own. The Association of Plastic Recyclers rates a co-extruded EVOH barrier layer up to 10 wt% as "Preferred" for PE flexible packaging when the tie layer carries more than 0.1 wt% grafted MAH, and it rates adhesive lamination with EVOH up to 5 wt% the same way.

FUSABOND and ADMER are the tie resins named in our source library for this role. Structures built this way, PE/EVOH and PE/PA among them, are treated in full under compatibilizers for multilayer film recycling.

What Is the Right Dosage of a Maleic Anhydride Grafted Polymer?#

Maleic anhydride grafted polymers are used at about 2 to 10 wt% when they compatibilize two polymers and about 1 to 5 wt% when they couple a polymer to a filler or fibre, with the exact level set by the graft content of the grade and by the amount of reactive partner it has to reach. Four factors drive the dosage inside those ranges.

• The grafted anhydride content of the grade, since a higher-graft grade delivers more reactive anhydride per kilogram added
• The amount of reactive partner available, whether that is fibre loading, minor-phase fraction, or the amine end-group concentration of a polyamide
• The property being bought, since the optimum for flexural strength is not always the optimum for tensile strength or impact strength in the same compound
• The residence time and temperature available in the extruder, which set how much of the added anhydride actually reacts before the melt exits the die

A worked calculation shows how little anhydride actually reaches the compound: 3 wt% of a grade carrying 1.0 % grafted MAH delivers 0.03 % anhydride to the compound (0.03 x 1.0 % = 0.0003, or 300 ppm). This is a calculation example, not a specification, and it can be checked against a specific grade and loading with the additive dosage calculator.

More is not always better. Above the optimum for a given property, the excess maleated polymer behaves as a low-molar-mass diluent in the matrix rather than an active coupling agent, a direct consequence of the molar-mass loss that comes with a higher graft level, and mechanical properties can fall again past that point instead of continuing to rise.

How Do Maleated Polyolefins Behave in Compounding and Processing?#

Maleated polyolefins are added as neat pellets in the main feed of a co-rotating twin-screw extruder, and the compatibilizing reaction happens in the same pass that disperses the phases. Co-rotating twin-screw extruders give higher axial velocity and mixing than counter-rotating designs, which is why they are the standard equipment for plastic compounding involving a maleated compatibilizer; vented two-stage screws for this duty typically run at an L/D ratio of 36:1.

Moisture, storage and anhydride hydrolysis#

Grafted anhydride rings hydrolyse to the corresponding diacid when they meet moisture, and a hydrolysed graft no longer forms the imide or ester link that the compound was bought for. Three storage rules follow directly from that chemistry.

• Keep unopened bags sealed until use, since the anhydride ring reacts with atmospheric moisture over time
• Dry the material before processing whenever the supplier's datasheet calls for it
• Follow the specific grade's datasheet rather than a generic drying protocol, because no single drying temperature or time is established in our source library for maleated polyolefins as a class

How is the effect of a maleated compatibilizer measured?#

The effect of a maleated compatibilizer is measured on 4 properties: notched impact strength, tensile and flexural strength, melt flow rate and, in wood-plastic composites, water absorption. No standard method for measuring grafted anhydride content itself is established in our source library, so this page names no titration protocol or FTIR wavenumber for that measurement.

Specimen geometry and unit conversion between the ASTM and ISO methods are covered on impact strength (Izod, Charpy).

Which Regulations Apply to Maleic Anhydride Grafted Polymers?#

A maleic anhydride grafted polymer is regulated through its monomers, not as a substance in its own right: polymers are exempt from REACH registration under Article 2(9) of Regulation (EC) No 1907/2006, and their EU food-contact status follows from the monomers on the Union list of Regulation (EU) No 10/2011. The word "approved" is never accurate for a food-contact plastic; the correct wording is "listed" or "cleared under" a specific section, which is how each instrument is cited below.

REACH: the polymer exemption and the monomer#

Maleated polyolefins carry no REACH registration number, because Article 2(9) of Regulation (EC) No 1907/2006 exempts polymers from registration, while their monomers are registered: maleic anhydride (CAS 108-31-6) holds more than 100 active dossiers. Neither maleic anhydride nor any maleated polymer covered on this page appears on the REACH Candidate List, checked 2026-09-22. The polymer exemption and how it interacts with the rest of the additive system are explained in full on REACH and plastic additives.

EU food contact: maleic anhydride FCM 234#

A maleated polyolefin may be used in EU food-contact plastics because every one of its monomers is on the Union list: maleic anhydride as FCM 234, under group restriction 3 with a total specific migration limit of 30 mg/kg expressed as maleic acid, and the backbone monomers propylene (FCM 275) and ethylene (FCM 125) without a specific limit. The 30 mg/kg figure is never stated as an SML of the grafted polymer itself; it belongs to the monomer, and it is a group limit shared with maleic acid, FCM 248, under the consolidated text of the regulation dated 16 March 2025.

Group restrictions, SML(T) values and the overall migration limit that sits alongside this one are decoded in full on EU 10/2011.

US FDA: what 21 CFR does and does not cover#

US food-contact clearance for maleated polyolefins is narrower than most datasheets suggest: 21 CFR 177.1520 covers ethylene-maleic anhydride copolymers with up to 2 % anhydride as an adhesive or sealant layer at or below 49 °C, and 21 CFR 177.1350 covers maleic-anhydride-grafted EVA, but no generic listing for PP-g-MAH exists. That gap is stated as a gap, not as a prohibition: clearance for a specific PP-g-MAH grade runs through a Food Contact Notification or a supplier letter rather than through a listing that covers the whole chemical class.

PPWR recycled-content targets and design for recycling#

Recycled-content law is the main demand driver for maleated compatibilizers: Regulation (EU) 2025/40 (PPWR) applies from 12 August 2026 and its Article 7 requires 35 % post-consumer recycled content in general plastic packaging and 30 % in contact-sensitive PET packaging from 2030. The 2030 targets step up further by 2040, to 65 % for general plastic packaging and single-use beverage bottles, 50 % for contact-sensitive PET and 25 % for contact-sensitive non-PET packaging. Every additive-relevant article of the EU Packaging and Packaging Waste Regulation (PPWR) is listed with its date on the regulation's own page.

Who Supplies Maleic Anhydride Grafted Polymers?#

Maleic anhydride grafted polymers come from SI Group (POLYBOND), Dow (FUSABOND), SK Functional Polymer (OREVAC), Mitsui (ADMER) and BYK (Scona), together with Chinese producers such as Coace and Baoxu, and the same backbone and graft level are sold under more than one of these brand names. Buyers should compare grades by backbone, grafted anhydride content and melt flow rate, not by trade name, since two products with different brand names can share the same underlying chemistry.

SI Group completed a recapitalization on 23 December 2025 and, besides POLYBOND, carries the ETHANOX, WESTON, ANOX, LOWINOX, NAUGARD and EVERCYCLE brand lines. Plants, certifications and regional coverage for the wider group of producers are in the directory of compatibilizer and coupling agent suppliers. Cross-check a grade against an equivalent from another producer with the plastic additive trade name lookup.

Request quotes for maleic anhydride grafted polymers: backbone, graft level, volume, blend pair and country, through the plastic additive supplier finder.

What Other Compatibilizers and Coupling Agents Replace Maleic Anhydride Grafts?#

Maleic anhydride is one of 3 reactive chemistries used to compatibilize polymer blends, next to epoxy-functional grafts built on glycidyl methacrylate and acid-functional copolymers such as EAA and ionomers, and it competes with silanes and titanates wherever the partner is a mineral surface. The choice between them follows the reactive partner: an ester-forming epoxide suits a polyester phase better than an anhydride does, and a non-reactive block copolymer avoids grafting chemistry altogether.

GMA-functional compatibilizers#

Glycidyl methacrylate functional compatibilizers take over where the partner is a polyester: the epoxide reacts with carboxyl and hydroxyl end groups rather than with amines, which makes E-MA-GMA the standard choice for PET and PBT blends. LOTADER AX8900 carries 24 wt% methyl acrylate and 8 wt% GMA, with an MFI of 6 g/10 min at 190 °C/2.16 kg, a melting point of 65 °C and a density of 0.94 g/cm³; ELVALOY PTW is built from ethylene (66.75 wt%), n-butyl acrylate (28 wt%) and GMA (5.25 wt%). The residual GMA monomer, not the copolymer itself, carries a harmonised Carc. 1B, Muta. 2 and Repr. 1B classification, an EU food-contact SML of 0.02 mg/kg under FCM 220, and a California Proposition 65 cancer listing dated 27 January 2023. Grades and hazard data for glycidyl methacrylate (GMA) functional compatibilizers sit on their own page.

Non-reactive block copolymer compatibilizers for polymer blends#

Non-reactive compatibilizers are added ready-made instead of being formed in the extruder: a block copolymer whose segments are miscible with each phase, such as SEBS in PP/PS or a PP-based olefin block copolymer in iPP/HDPE, parks at the interface without any chemical reaction. INTUNE, a PP-based olefin block copolymer, reduced domain size in an iPP/HDPE blend at 5 wt%, and the di-block Polarfin from Interface Polymers is used the same way in PE/PP films. Blend-pair recommendations across this whole non-reactive class are collected under compatibilizers for polymer blends.

Silane coupling agents on mineral fillers#

Silane coupling agents are the alternative wherever the surface carries hydroxyl groups a silanol can condense with: they work on silica, quartz and glass at 0.2 to 1.0 wt% of the mix, and they fail on calcium carbonate, which is treated with titanates or stearic acid instead. Beyond calcium carbonate, silanes also perform poorly on gypsum, barytes, graphite and carbon black, and only slightly better on talc and titanium dioxide, which narrows their practical use to siliceous fillers. Hydrolysis conditions, deposition methods and filler loadings for the whole class are on silane coupling agents.

Is maleic anhydride grafted polypropylene the same as maleic anhydride?#

No: maleic anhydride (CAS 108-31-6) is a small cyclic anhydride used as a monomer, while maleic anhydride grafted polypropylene (CAS 25722-45-6) is a polymer that carries a fraction of a percent of those rings attached to its chains. The grafted units on the finished polymer are succinic-anhydride rings, formed once the anhydride has added to the polyolefin backbone, not free maleic anhydride molecules mixed into the resin.

Does a maleated polyolefin stay in the recycling stream?#

A maleated polyolefin stays in the material: it is a polymer, it does not evaporate or migrate out, and Scholz and co-workers noted in 2026 that compatibilizers themselves become legacy additives in the next recycling stream. The APR Design Guide nonetheless rates a PE-g-MAH tie layer carrying more than 0.1 wt% MAH, used with up to 10 wt% co-extruded EVOH, as "Preferred" for PE flexible packaging, since staying in the material is exactly what a tie layer is supposed to do. Broader rules for keeping additive packages compatible with the next recycling pass are collected under design for recycling.

Is maleic anhydride hazardous in a grafted polymer?#

The hazard belongs to the monomer, not to the pellet: maleic anhydride has a harmonised CLP classification as a respiratory sensitiser (H334), a skin sensitiser (H317) and a skin-corrosive substance (H314), while the grafted polymers themselves carry no harmonised classification and are not on the REACH Candidate List. No residual free-monomer content for any grafted grade is established in our source library, so a formulator working with these hazards should consult the specific grade's safety data sheet rather than a class-level figure.

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