# Thermoplastic polymers based on renewable carbohydrates (including alginates, polysaccharides, starches)

Topic radar · 5,419 documents · 2021-01-01–2026-11-02 · updated 2026-10-31

Canonical: https://slate.greyb.com/radar/thermoplastic-polymers-based-on-renewable-carbohydrates-including-alginates-polysaccharides-starches/innovations

## In one minute

### Starch is melted by breaking its own hydrogen bonds, and the plasticiser is the whole trick
Starch decomposes near 150 °C before it flows, so every melt route starts by forcing small molecules between the chains. The filings differ mainly in what those molecules are. One composition carries 60–95% starch against 5–35% plasticiser and specifies the result as a melt flow rate of at least 0.01 g/10 min at 160 °C [1]. Another pushes starch to 80–85% and splits the plasticiser into a salt and an alcohol: calcium chloride at 2–5% plus a glycerol/diglycerol/decaglycerol blend at 10–18% [2]. A third dries the starch below 5% moisture first and plasticises it with a non-aqueous agent at 15–50%, which avoids the gelatinisation step entirely [3].

The more interesting variants add chemistry rather than more plasticiser. Agrana's route pairs a polyol with 0.1–6% epoxidised vegetable oil and a carboxylic acid, and is explicitly free of polyester urethane [4]. Samyang builds the plasticiser from an anhydrosugar alcohol and defines it by number-average molecular weight of 193–1,589 g/mol and 2.54–21.36 hydroxyls per molecule, which is a way of specifying plasticiser performance instead of naming a chemical [5].

One route does the work inside the extruder. A small-molecule precursor, methylol urea, is mixed into starch, penetrates the granule, and then polymerises during the screw run, so the macromolecular plasticiser forms in place and the melting point drops below the decomposition point [6]. Water is the plasticiser in the seaweed work: a *Ulva* polysaccharide is run at 20–60% water as a flowable hydrated powder and hot-melt processed, with the patent reporting better load and strain than solvent-cast controls [7].

1. [JP2025152918A](/?paper=JP2025152918A&utm_source=radar&utm_medium=dashboard)
2. [CN114539633B](/?paper=CN114539633B&utm_source=radar&utm_medium=dashboard)
3. [CN114058086A](/?paper=CN114058086A&utm_source=radar&utm_medium=dashboard)
4. [ES2950810T3](/?paper=ES2950810T3&utm_source=radar&utm_medium=dashboard)
5. [KR102433225B1](/?paper=KR102433225B1&utm_source=radar&utm_medium=dashboard)
6. [CN114589831A](/?paper=CN114589831A&utm_source=radar&utm_medium=dashboard)
7. [CN121443527A](/?paper=CN121443527A&utm_source=radar&utm_medium=dashboard)

### The capacity being announced is polyester and monomer, at a scale starch compounds never reach
Futerro started a 30,000 t/yr PLA line at Bengbu fed by an 80,000 t lactic acid unit. NatureWorks built a fully integrated complex in Nakhon Sawan covering lactic acid fermentation, lactide and polymerisation. Balrampur Chini commissioned India's first industrial PLA plant and took its first institutional order, compostable garbage bags for the Lucknow Cantonment Board, before the plant was even at rate. Qore added a 66,000 t 1,4-butanediol plant on dent corn, which feeds the polyester half of every blend in this record.


### The interface work has settled into a few compounders iterating on one problem
Three filings from a single Anhui applicant within six weeks attack the same boundary three ways: maleic-anhydride-grafted PBAT oligomers fixed onto enzyme-etched starch with no small-molecule plasticiser, to stop migration; a phytic acid and xylo-oligosaccharide modifier with hypophosphite, to stop water displacing the interfacial hydrogen bonds under humid heat; and a staged melt sequence that predisposes modified starch into PLA before PBAT and chain extender are post-added. Kingfa's contribution in the same period fixes the polyester by the molar share of terephthalate at 53% and pairs it with 20–35 parts crosslinked starch.


### The commercial product is a masterbatch, and that shapes the chemistry
The intermediate, not the resin, is what gets sold. A Japanese masterbatch carries over 60 wt% starch at a melt flow rate of 3.3–4.2 g/10 min and is designed to be let down into a carrier resin until the final compound holds at least 25% starch. Japanese and Taiwanese filings in the same family treat strand brittleness at high starch loading as the problem to solve, adding a compatibiliser matched to the carrier's melt flow rate so pellets can be cut without shattering. A starch masterbatch for PBS loading goes up to 30% addition without loss of strength.


### The deepest patent portfolio in this field is written for a converter, not a shopper
Daesang's filings read like a purchasing specification. They fix melt flow index at 2–5 g/10 min at 190 °C with film impact of 3–6 kgf·cm, hold colour at L ≥ 80 and b ≤ 16, and add essential oils to mask the burnt odour starch gives off when it is over-worked in the barrel. No consumer brand puts odour masking on a pack. A converter running a new compound on an existing blown-film line asks for exactly those numbers.


### The coating route now has suppliers who own either the paper or the colloid
CHT's water-based barrier is built on depolymerised polygalactomannan and depolymerised alginate, runs on blade, air-knife or curtain coaters, and is written expressly as a compliant replacement for the fluorochemical grease barrier. Stora Enso laminates a microfibrillated cellulose film to paperboard with a water-soluble thermoplastic adhesive and specifies both a water vapour transmission rate and a repulping reject rate. Plantic coats paper with a modified starch held at 45% amylose or above alongside polyvinyl alcohol, and a Brazilian filing targets repulpable carton lamination with a PBAT, PBS and thermoplastic starch layer.


### Starch content falls as the format gets thinner or more demanding
Read the compositions in sequence and the trade-off is explicit. The high-starch end is cost-driven and thick-walled; the film and barrier end gives starch up.


### One barrier film protects a number a buyer can measure on delivery
Plantic specifies film at 10–600 µm with haze under 25%, and holds oxygen barrier at 75% relative humidity by choosing a polyol plasticiser with a glass transition at or above 25 °C. Its PVA phase is pinned to dispersed domains of 50–300 nm, which is the variable that decides whether the film stays clear.


## Overview


The documents behind this radar describe one materials problem and five different commercial answers, and the answers have less in common than the feedstock does. Starch decomposes before it flows, so every route in the record is a workaround for that single fact, and the routes sort by how much carbohydrate they can carry. Derivatise the chain and it becomes a genuine thermoplastic: a cellulose ester with controlled side-chain length spins at 120–150 °C. Plasticise it and you can push starch to 60–95% of the compound. Dilute it into a polyester and the starch falls to 5–35 parts against 47–94 parts polyester, described in the filings as a cost-reducing filler rather than the matrix. Dissolve and gel it instead, and the polysaccharide leaves thermoplastic processing altogether, as alginate spun from a calcium bath.


## What's new


October produced 59 documents against September's 97. Almost the whole fall sits in one place: biomedical and hydrogel filings dropped from 47 to 22, packaging slipped from 18 patents to 13, and food service rose from six to seven. One month does not make a slowdown, and the drop is spread across filers, so no single organisation going quiet explains it. Read the number as a pause in academic and hospital dressing filings.


## Research

### The claimed invention has moved onto a measured number
Most of the recent film filings no longer claim a composition. They claim a property of a bought-in input. Kingfa defines its thermoplastic starch by a 10–40% mass loss between 100 and 200 °C, and the loss window is the claim. The same applicant defines the PLA by the ratio of its melt flow rate after two hours in 80 °C water to the value before, constrained between 1.1 and 5.0, and the polyester by a 100 Hz storage modulus of 70,000–300,000 Pa.


### Compatibilisation has become a placed molecule with a stated architecture
The interface between hydrophilic starch and a hydrophobic polyester is where the technical differentiation now sits, and the filings specify where the compatibiliser goes as well as what it is. One route grafts maleic anhydride onto PLLA with dicumyl peroxide, then chain-extends with MDI, before blending with glycerol/formamide-plasticised starch. Another uses a terpolymer of ethylene elastomer, maleic anhydride and glycidyl methacrylate alongside starch that has itself been modified with maleic anhydride and GMA, so both phases carry reactive groups.


### Layer adhesion is the interface that is still unsolved
The multilayer work exposes the gap. Winpak's answer is an amine-functional adhesion promoter, polyethylenimine at 0.05–10 wt%, added to a 30–96 wt% starch layer so it bonds to an adjacent polyester skin. That is a different problem from barrier. The barrier filings solve their own problem by specifying a molecular weight distribution above 6.5 across a high-molecular-weight starch, a low-molecular-weight starch and a water-soluble polymer, and the PVA side is stabilised against degradation with a boric acid/hypophosphorous acid compound. Neither of those addresses whether the layer stays attached through a converting line.


### Seaweed polysaccharides flow only with very high plasticiser fractions, and molecular weight is the control variable
The marine branch solves the same melting problem with much more plasticiser and much less polymer. One extrudable formulation carries the hydrocolloid at 30–80% of total weight against 20–70% plasticiser, plus 1–80% of a biobased biodegradable polymer and 5–50% of a reactor-derived biosurfactant. Another runs the alginate through reactive extrusion with no water and no solvent, using a plasticiser, a crosslinker and a lubricant. Notpla's route sets a floor of at least 30 wt% seaweed material with a plasticiser that must contain water or a C–H bond, and a related filing claims a single extrusion pass at 50 wt% seaweed or more.


### In hydrogels, calcium supply is the design variable, not the polymer choice
The gel work is crosslinking engineering, and the interesting part is how the calcium gets delivered. A sodium alginate/gelatin dressing grafts methacrylic anhydride onto gelatin and dopamine onto alginate to make an interpenetrating network with 10–30 µm pores. A chitosan/alginate dressing with barium titanate uses EDC/NHS chemical crosslinking alongside ionic bridging to get both strength and antibacterial action from one network.


### Mulch film decouples service life from degradation by stacking the layers
Every mulch filing is a settlement of the same conflict: the film must survive a season and then disappear. The answers are layered. A three-layer film puts an anti-hydrolysis agent in both outer skins and the starch with calcium and magnesium carbonate in a middle layer carrying 50% of the mass. A two-layer film puts 15–25% TPS in one layer and 50–60% TPS with an oxidation promoter in the other, so one side goes first.


### Alginate fibre is spun from a bath, and the bath chemistry is the invention
The fibre branch is not thermoplastic processing at all. The standard route spins sodium alginate into a calcium chloride bath, and the filings replace or extend that bath. One substitutes an acidic bath at pH below 4 containing a polyhydric alcohol, so the alcohol esterifies the alginate as it coagulates, producing a hydrophobic, acid-resistant fibre and a recyclable bath.


### Printed and rubber-toughened formats keep the starch share high
Where the article is thick and the tolerances loose, starch stays dominant. FDM filament runs thermoplastic starch with PVA at 90/10 through 60/40, plasticised with 45% glycerol and 15% water relative to polymer mass, extruded at 150–190 °C. Grupa Azoty's printing composition is 80–99.5% thermoplastic starch with no more than 20% PVA or PBAT, produced by a two-stage extrusion that granulates the starch before combining it with the synthetic polymer.


### Flame retardancy uses the carbohydrate as a char source, and the loadings are an order of magnitude higher
This is chemistry that happens to share a feedstock. The intumescent approach needs an acid source, a carbon source and a gas source, and starch is a natural carbon source because of its hydroxyl density. Fuzhou University integrates all three onto one molecule: starch is phosphated, then reacted with amino acids and an aluminium-containing amino acid, giving a single-component additive. A later filing uses itaconic acid as the bridge, esterifying starch and DOPO on one side and melamine phosphate on the other. Jiangnan's version applies choline phytate to thermoplastic starch, where the starch itself is the carbon source.


### What the engineering record does not close
The layer-by-layer designs solve a real problem and cannot demonstrate it. A three-layer mulch film, a gradient hydrogel or a core-shell degradation regulator all depend on differences between layers or between months, and the standard whole-sample respirometry test that governs whether a mulch film may be sold measures only total carbon conversion. Nothing in these documents reports a per-layer or time-resolved result for the architectures they claim.


## Market

### Seaweed's public milestones are a regulatory clearance and an ownership change
Kelpi's coating passed the US food-contact notification route for paper and board in contact with all food types under all conditions, which opens personal care and cosmetic packaging as well as food. On the supply side, JRS bought Algaia two years after acquiring DuPont's former alginate business, putting two Brittany alginate producers under one owner.


### Starch film products in public run to one plant and one region each
Natupla describes a move from laboratory project to a pilot plant it calls market-ready, selling packaging for exported fruit. A potato-starch thermoplastic for single-use bags came out of an Austrian research institute working with a consumer-goods partner. Both are statements that a line exists, at a scale one site can carry.


### The flame-retardant line has patents and no product voice
Konica Minolta uses the polysaccharide itself as the flame retardant in a thermoplastic resin, specifying 0.2–1.5 acidic functional groups per monosaccharide unit so that carrageenan or alginate dehydrates into char, and naming cosmetic housings for electronic equipment as the application. That is an equipment maker writing a material spec for its own enclosures.


### The performance claims that are published are the suppliers' own
The tensile figures, melt indices and barrier numbers attached to these materials come from the applicant's worked example or the supplier's data sheet. Nothing in this record is an independent test of a marketed starch compound, and the one regulatory milestone anyone can check, Kelpi's clearance, certifies food-contact safety rather than barrier performance. For a buyer, that means the first qualifying step is still running the material on your own line.


## Strategy

### The seaweed melt camp is a set of small specialists with no stake in feedstock or conversion
Flexsea claims an extrudable formulation at 30–80% algal hydrocolloid against 20–70% plasticiser plus a reactor-derived biosurfactant. Biolabmate runs alginate through water-free, solvent-free reactive extrusion. Sway blends up to 90% phycocolloid with PBAT for home compostability. Viable Gear claims a dope at 50% or more algal solids that names coating and spinning alongside extrusion, then a separate compound taking nanocellulose from alginate production by-product into a PHA blend. The Israeli Ulva work hot-melts the polysaccharide at 20–60% water.


### The biomedical filings are clinical-device filings, and the polysaccharide is the passive layer
Gansu's sensor institute claims a dual-network alginate hydrogel for strain sensing and a dressing that powers itself hydrovoltaically. A stomatology hospital claims a tremella polysaccharide sensor for spinal posture. Tianjin University files sweat glucose monitoring; North University of China files a microneedle patch that monitors and releases drug in a closed loop; Beijing Institute of Technology files a bilayer electrode for bioelectric signals; a central hospital files one pad doing ECG and ultrasound coupling.


### Mulch film has drawn the chemical majors in, and they claim a rheology rather than a certificate
LG Chem's filings on the same PBAT and thermoplastic starch composition claim it through a non-recoverable storage-modulus area of 1,000–10,000 Pa·log%, measured across a strain sweep at 150 °C. LG Hausys takes the adjacent route with 10–60% thermoplastic starch and maleic-acid-esterified PBAT. Beside them, the provincial filings have moved from making the film disappear to making it deliver something while it does: three-layer staged nutrient release, a two-layer gradient with a starch-phosphate fertiliser in the atmosphere-facing layer, a core-shell regulator that holds structure past 90 days and then triggers, and a PHA film built on alkyl-grafted starch with mesoporous silica.


### Nobody has taken the platform position, and the chemistry to do it is already in the record
Every substantial applicant holds a format, not a platform. LG Chem and LG Hausys are in mulch. Kingfa and the Anhui and Suzhou compounders are in film. Bio Tec specifies pea starch at 25% or more of total starch for film and moulded parts. Stora Enso and CHT are in coated paper. None of them files across two areas.


## Areas

- Packaging & Films · 1,676 documents
- Biomedical & Hydrogels · 1,056 documents
- Food Service & Disposables · 695 documents
- Agriculture & Environmental · 245 documents
- Industrial & Consumer Materials · 1,697 documents
- Policy & Lifecycle · 15 documents