Structure, Degradation Behavior, and Applications of Poly(trimethylene carbonate) (PTMC) in Flexible Absorbable Materials

1 Key Considerations for Degradable Materials

In biomedical materials, “degradable” does not necessarily mean “suitable for implantation.” The fact that a material can degrade in vivo only indicates that it can be gradually broken down or absorbed. What truly determines its application value is how it degrades, what degradation products are generated, how its mechanical properties change during degradation, and whether it affects the local tissue environment.

Many common aliphatic polyesters, such as poly(lactic acid) (PLA), poly(glycolic acid) (PGA), and poly(lactic-co-glycolic acid) (PLGA), can gradually degrade in vivo through hydrolysis. However, their degradation may generate carboxylic acid-containing products. If these acidic products accumulate locally, they may cause a decrease in pH, further affecting tissue response, cell activity, and the degradation rate of the material itself.

Poly(trimethylene carbonate) (PTMC) is an aliphatic polycarbonate. It is characterized by a flexible backbone, a relatively low glass transition temperature, a generally amorphous structure, non-acidic degradation products, and relatively pronounced surface erosion behavior under in vivo and enzyme-assisted conditions.

2 Structural Origin of PTMC: Carbonate Bonds and Flexible Trimethylene Segments

2.1 Basic Structure of PTMC

PTMC is typically prepared by ring-opening polymerization (ROP) of trimethylene carbonate (TMC).

The repeating structure of PTMC can be represented as:

–[O–CH2–CH2–CH2–O–C(=O)]n–

It can also be abbreviated as:

–[O–(CH2)3–O–C(=O)]n–

This repeating unit contains two key structural features that determine material performance:

Structural Unit	Structural Role	Effect on Material Properties
–CH2–CH2–CH2–	Flexible aliphatic segment	Enhances segmental mobility, making the material softer and more elastic
–O–C(=O)–O–	Carbonate bond	Distinguishes PTMC from aliphatic polyesters and affects its degradation products and degradation mode

An important difference between PTMC and PLA, PGA, or PLGA is that PTMC contains carbonate bonds in its main chain, whereas PLA, PGA, and PLGA mainly contain ester bonds. This structural difference is an important source of the differences in degradation behavior and local tissue response between these materials.

2.2 Formation of PTMC by Ring-Opening Polymerization of TMC

TMC is a six-membered cyclic carbonate monomer. During ring-opening polymerization, the cyclic monomer is opened and continuously polymerized to form linear PTMC molecular chains. The significance of this reaction is not only to obtain the polymer, but also to regulate the molecular weight, molecular weight distribution, end-group structure, and copolymer composition of PTMC. For practical applications, these factors influence the viscoelasticity, film-forming ability, mechanical strength, processability, material morphology, and degradation period of the material.

3 How Structure Determines Performance: Low Tg, Flexibility, and Amorphous Characteristics

3.1 Flexible Backbone Makes PTMC More Similar to an Elastic Material at Body Temperature

The –CH2–CH2–CH2– aliphatic segments in the PTMC backbone have strong segmental mobility. Compared with polymers that are more rigid or more highly crystalline, PTMC generally exhibits better flexibility and elasticity.

Literature reports that PTMC is typically a hydrophobic, amorphous polymer, with a glass transition temperature, Tg, commonly around −15 to −20 °C. Because its Tg is below room temperature and body temperature, PTMC does not readily behave as a hard and brittle glassy material under common use conditions. Instead, it is closer to a soft, rubber-like, or elastic material.

3.2 Matching Flexibility with Applications: PTMC Is More Suitable for Low-Load Soft-Tissue Scenarios

For high-load bone fixation devices, hard-tissue support materials, and similar applications, pure PTMC usually lacks sufficient strength and stiffness. It often needs to be reinforced through copolymerization, crosslinking, or composite design to meet application requirements. In contrast, for soft-tissue scaffolds, absorbable barrier membranes, nerve conduits, flexible coatings, and drug delivery carriers, material flexibility, elasticity, and low mechanical irritation are more important.

The low Tg and flexible chain segments of PTMC allow it to better adapt to the soft-tissue environment at body temperature. However, in practical design, strength, degradation period, shape stability, and tissue response must still be considered simultaneously.

4 Core Degradation Characteristics of PTMC: Non-Acidic Products and Surface Erosion

4.1 Key Differences Between PTMC and PLA/PLGA

PTMC, PLA, and PLGA are all common degradable biomedical polymers, but their main-chain structures, degradation modes, and suitable application directions are different. PTMC is an aliphatic polycarbonate, whereas PLA and PLGA are aliphatic polyesters. This structural difference determines their different degradation behavior in vivo.

Comparison Dimension	PTMC	PLA/PLGA
Material type	Aliphatic polycarbonate	Aliphatic polyester
Key linkage in the main chain	Carbonate bond	Ester bond
General hydrolysis behavior	Hydrolysis is relatively slow under non-enzymatic conditions, and the material is relatively stable	Ester bonds can undergo hydrolysis, which is an important degradation pathway
Main degradation mode	Relatively stable under non-enzymatic hydrolysis; under in vivo or enzyme-assisted conditions, it often gradually erodes from the material surface	Often undergoes bulk hydrolysis after water enters the interior of the material
Degradation product characteristics	Does not accumulate carboxylic acid products such as lactic acid or glycolic acid; the risk of local acidification is lower	Can generate acidic products such as lactic acid and glycolic acid; local accumulation may reduce pH
Mechanical characteristics	Low Tg, soft, and relatively elastic; more suitable for flexible material design	PLA is usually relatively stiff; PLGA performance is strongly affected by the lactic acid/glycolic acid ratio and molecular weight
Suitable application directions	Soft-tissue materials, flexible absorbable membranes, drug delivery systems, injectable microspheres, etc.	Sutures, bone fixation materials, drug delivery microspheres, absorbable scaffolds, etc.

The advantage of PTMC is that it provides an alternative material option. When an application places greater emphasis on softness, non-acidic degradation, and relatively mild surface erosion, PTMC has advantages. When an application requires higher initial strength, a more mature drug delivery platform, or hard-tissue-related support, PLA and PLGA still have important value.

4.2 Surface Erosion Supports Shape Retention and Release Control

The degradation modes of degradable polymers are usually divided into bulk degradation and surface erosion. These two modes have significantly different effects on material performance.

Bulk degradation:

Water enters the interior of the material → Chain scission occurs both internally and at the surface → Molecular weight decreases → The material may crack, become brittle, or rapidly lose mechanical performance

Surface erosion:

Degradation mainly occurs at the material surface → Surface chain segments gradually break and detach → The material loses mass layer by layer from the outside inward → The internal structure is relatively maintained

Under in vivo and enzyme-assisted conditions, PTMC often shows degradation characteristics dominated by surface erosion. This degradation mode is important for biomedical materials:

Surface Erosion Feature	Effect on Applications
The material loses mass layer by layer	Helps reduce the risk of sudden structural instability caused by bulk degradation, although shape retention still depends on molecular weight, crosslinking, thickness, and pore structure
The internal structure is relatively maintained	Helps delay abrupt loss of mechanical performance
Degradation is related to surface area	Allows degradation rate to be adjusted through morphology and size
The surface layer is gradually eroded	Helps support the design of drug release processes

4.3 Non-Acidic Degradation Products Reduce the Risk of Local Acidification

When aliphatic polyesters such as PLA, PGA, and PLGA degrade, they can form small molecules or oligomers containing carboxylic acid groups. If these acidic products accumulate in local tissues, they may reduce pH and accelerate degradation of the material itself, producing an autocatalytic effect.

The degradation process of PTMC is not characterized by the accumulation of acidic carboxylic acids. Literature studies indicate that PTMC degradation is not mainly associated with the accumulation of carboxylic acid products such as lactic acid or glycolic acid. After carbonate bond cleavage, PTMC can form low-molecular-weight carbonate fragments, 1,3-propanediol, and carbonate/carbon dioxide-related products, which are then further metabolized or eliminated.

PTMC surface carbonate bond cleavage → Low-molecular-weight carbonate fragments, 1,3-propanediol, and carbonate/carbon dioxide-related products → Further metabolism or elimination

The fact that PTMC degradation is not characterized by acidic carboxylic acid accumulation is highly important for implantable materials. The local tissue environment is sensitive to pH, inflammatory responses, and cell activity. PTMC helps avoid the risks associated with acidic product accumulation seen in many polyester materials, giving it application value in soft-tissue repair, long-term drug release, and absorbable implants.

5 How Enzymes and Cells Participate in PTMC Degradation

5.1 PTMC Is Relatively Stable Under Ordinary Hydrolysis

Compared with some aliphatic polyesters, PTMC is relatively stable under non-enzymatic hydrolysis. Its in vivo degradation depends more on biological processes occurring at the material surface, including enzymatic action, cell-mediated foreign body reactions, and the influence of the local tissue environment.

This means that judging the in vivo degradation rate of PTMC solely through in vitro hydrolysis experiments in buffer solution is not sufficient. In a real in vivo environment, protein adsorption, macrophage adhesion, enzyme secretion, tissue fluid exchange, local oxidative conditions, and mechanical stress may all affect the surface erosion process of PTMC.

5.2 Macrophages and Lipases Participate in Surface Erosion

Recent studies suggest that in vivo surface erosion of PTMC may be related to macrophage behavior during the foreign body response and to lipases secreted by these cells. This is one of the important mechanisms of PTMC degradation in vivo. After a material is implanted, protein adsorption occurs on its surface. Subsequently, immune cells such as macrophages may adhere to, accumulate on, or fuse at the material surface, and they may release lipases and other degradation-related factors that can promote carbonate bond cleavage in the PTMC surface layer.

This process can be simplified as follows:

PTMC material surface → Protein adsorption → Macrophage adhesion, accumulation, or fusion → Release of lipases and other degradation-related factors → Carbonate bond cleavage in the surface layer → Gradual surface erosion of the material

The in vivo degradation of PTMC is closely related to the surface properties of the material and local biological responses. For the same PTMC material, if it is fabricated into bulk materials, films, microspheres, or porous scaffolds, its degradation rate and tissue response may differ because of differences in surface area, surface roughness, cell contact mode, and extent of enzymatic action.

6 How to Regulate PTMC Performance: Molecular Weight, Crosslinking, Copolymerization, and Morphological Design

6.1 Molecular Weight Affects Mechanical Properties, Processability, and Degradation Period

The molecular weight of PTMC has a significant influence on material performance. Low-molecular-weight PTMC may be tacky and soft, insufficient in strength, or poor in shape stability. Higher-molecular-weight PTMC generally has better film-forming ability, elasticity, and mechanical integrity. However, higher molecular weight is not always better. An increase in molecular weight affects melt processing, solution processing, segmental mobility, surface erosion rate, and drug release behavior. In practical applications, an appropriate molecular weight should be selected according to the target use.

Application Direction	Main Requirements for PTMC
Flexible films and barrier materials	Good film-forming ability, certain elasticity, and shape-retention capability
Drug delivery carriers	Adjustable degradation rate and drug diffusion process
Injectable microspheres	Stable particle size, controllable surface morphology, and gradual absorption in vivo
Soft-tissue scaffolds	Softness and elasticity that match the mechanical characteristics of soft tissue

6.2 Crosslinking Improves Elastic Recovery and Shape Stability

In some applications, pure linear PTMC lacks sufficient strength and shape stability. Crosslinking can form a three-dimensional network structure by creating connection points between molecular chains, thereby improving elastic recovery and resistance to deformation.

 

The main effects of crosslinking on performance include:

Effect of Crosslinking	Specific Impact
Improves elastic recovery	The material can more easily recover its shape after deformation
Improves shape stability	Reduces the risk of material flow, deformation, or overly rapid collapse
Regulates degradation rate	Crosslink density affects the action of water, enzymes, and cells on the material surface
Improves scaffold performance	Facilitates the preparation of elastic films, porous scaffolds, and three-dimensional structural materials

If the crosslink density is too low, the reinforcing effect is limited. If the crosslink density is too high, segmental mobility may be reduced, affecting degradation rate and cellular responses. The key point of crosslinking design is to achieve a reasonable balance among elasticity, strength, and degradation behavior.

6.3 Copolymerization and Composite Design Compensate for the Limitations of PTMC Alone

The advantages of PTMC include softness, non-acidic degradation, and surface erosion. However, pure PTMC cannot meet all application requirements. Its strength, hydrophilicity, cell-recognition ability, and degradation period may all need further adjustment. Common modification strategies include:

Modification Strategy	Main Purpose
Copolymerization with PLA, PGA, PCL, etc.	Regulates strength, degradation period, and crystallization behavior
Introduction of hydrophilic segments such as PEG	Improves hydrophilicity, drug release, and water contact
Composite design with inorganic materials	Improves strength, osteoconductivity, or interfacial stability
Fabrication into microspheres, nanoparticles, or porous scaffolds	Changes surface area, release behavior, and tissue contact mode

Among these, polycaprolactone (PCL) is commonly used to regulate flexibility and degradation period, while polyethylene glycol (PEG) is commonly used to improve hydrophilicity and construct carrier systems.

It should be noted that copolymerization and composite design simultaneously alter multiple properties. For example, introducing polyester segments may improve strength or change the degradation period, but it may also introduce acidic degradation products. Introducing hydrophilic segments may improve water contact and drug release, but it may also change enzyme adsorption, cellular responses, and the surface erosion rate. Therefore, PTMC modification should be guided by specific application requirements.

7 Suitable Application Directions and Material Design Priorities for PTMC

7.1 Drug Delivery: Surface Erosion Helps Regulate the Release Process

Drug delivery materials need to control both the drug release rate and the degradation behavior of the carrier. The hydrophobicity, enzyme-assisted/in vivo surface erosion, and non-acidic degradation characteristics of PTMC make it suitable for the design of certain hydrophobic drug delivery systems or long-term release systems.

When PTMC is used as a drug delivery carrier, drug release is not determined by a single factor. Instead, it is jointly controlled by drug diffusion within the material and the gradual surface erosion of the PTMC carrier. Particle size, pore structure, surface area, membrane thickness, and enzyme and cellular responses at the implantation site can further affect the release rate and release duration.

Drug release from a PTMC carrier

↓

Main controlling factors:

1. Drug diffusion: migration of the drug from the PTMC matrix to the exterior

2. Surface erosion: gradual degradation of the PTMC surface layer, allowing the encapsulated drug to continue becoming exposed and released

Factors affecting release rate:

particle size / pore structure / surface area / membrane thickness / drug hydrophobicity / local enzyme and cellular responses

The design focus of PTMC-based drug delivery systems is to regulate both carrier structure and the drug release pathway. For example, smaller microspheres have a larger specific surface area, making drug diffusion and surface erosion generally easier to occur. Increased crosslink density or a thicker membrane layer may delay drug diffusion and carrier erosion.

7.2 Soft-Tissue Repair: Low Tg and Elasticity Support Mechanical Compliance Matching

Soft-tissue materials require greater attention to flexibility, elasticity, shape retention, and tissue compatibility. PTMC is generally in a flexible state at body temperature, making it suitable for soft-tissue-related material design. Suitable application directions for PTMC include:

Application Direction	Reason for Suitability
Soft-tissue scaffolds	Soft and elastic, helping reduce mechanical irritation caused by rigid materials
Nerve conduits	Flexibility helps reduce local compression and irritation
Absorbable barrier membranes	Can be gradually absorbed while maintaining certain elasticity and shape stability
Flexible coatings	Can improve the compliance and local contact condition of rigid substrate surfaces

However, in soft-tissue repair, PTMC cannot rely solely on its “softness.” The material also needs sufficient structural stability, an appropriate degradation period, and controllable tissue responses. Crosslinking, copolymerization, and composite design are often important approaches for improving practical application performance.

7.3 Injectable Microspheres: Material Properties Are Reflected in Particle Size and Surface Design

PTMC can be designed as microparticles or microspheres and combined with absorbable gel carriers for research or formulation exploration related to tissue filling, tissue augmentation, or local drug delivery systems. Related patents propose that PTMC can be used as a microparticle material in combination with an aqueous resorbable gel carrier, with emphasis on parameters such as microparticle size, sphericity, surface smoothness, and the rheological properties of the gel carrier.

These applications show that PTMC performance must be expressed through specific material forms. The design of injectable microspheres depends not only on polymer chemical structure, but also on particle size, surface morphology, molecular weight, and the carrier system.

Design Parameter	Impact
Microsphere particle size	Affects injectability, tissue distribution, surface area, and degradation rate
Surface smoothness	Affects cell adhesion, foreign body response, and tissue interaction
Molecular weight	Affects microsphere stability, degradation period, and mechanical behavior
Gel carrier	Affects the injection process, initial localization, and local morphology
Surface erosion	Affects gradual in vivo absorption and changes in material volume

7.4 Material Challenges to Be Addressed in PTMC Applications

Material Challenge to Be Addressed	Cause	Common Regulation Strategy
Limited mechanical strength of pure PTMC	The backbone is flexible and Tg is low, so the material behaves more like an elastic material than a highly rigid one	Enhance the material through crosslinking, copolymerization, or composite design to improve shape stability and resistance to deformation
Relatively strong surface hydrophobicity	The backbone lacks sufficient hydrophilic groups, which may affect protein adsorption, cell adhesion, and drug release	Introduce hydrophilic segments such as PEG or perform surface hydrophilic modification
Environmental variation in in vivo degradation rate	Enzymes, macrophages, implantation site, and local tissue responses all affect surface erosion	Combine in vitro enzymatic degradation experiments with in vivo evaluation to determine the actual degradation period
Material performance is strongly affected by morphology	Bulk materials, films, microspheres, and porous scaffolds differ in surface area, thickness, and pore structure	Design particle size, membrane thickness, pore structure, surface morphology, and crosslink density according to the intended application

8 Classification Tables of Chemicals Related to the Study of PTMC Structure, Degradation, Modification, and Applications

Table 1. Products Related to PTMC Synthesis, Monomer Preparation, and Polymerization Control

Detailed Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Core cyclic carbonate monomer for PTMC	2453-03-4	D155394	1,3-Dioxan-2-one (trimethylene carbonate, TMC)	≥98% (GC)	Trimethylene carbonate monomer used for the preparation of poly(trimethylene carbonate) by ring-opening polymerization; directly related to the construction of flexible aliphatic polycarbonate backbones
Diol precursor for TMC synthesis	504-63-2	P108208	1,3-Propanediol	≥98%	Used in studies on trimethylene carbonate monomer synthesis; can also serve as a reference compound related to non-acidic PTMC degradation products
Relatively green carbonylation reagent	616-38-6	D119695	Dimethyl carbonate (DMC)	Anhydrous, ≥99%	Used in carbonylation and transesterification reaction studies; related to synthetic routes for trimethylene carbonate monomer preparation
Aliphatic carbonate reagent	105-58-8	D103040	Diethyl carbonate (DEC)	≥99%	Used in aliphatic carbonate synthesis and transesterification reaction systems; supports research on cyclic carbonate monomer preparation
Aryl carbonate reagent	102-09-0	D106411	Diphenyl carbonate (DPC)	≥99%	Used in carbonate exchange reactions, polycarbonate synthesis, and cyclic carbonate-related reaction studies
Metal-catalyzed ring-opening polymerization catalyst	301-10-0	T100108	Stannous 2-ethylhexanoate	≥95%	Used for the ring-opening polymerization of cyclic monomers such as trimethylene carbonate, lactide, glycolide, and caprolactone; suitable for the preparation of PTMC and its copolymers
Organic base catalyst for ring-opening polymerization	6674-22-2	D106478	1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)	≥99%	Used in organocatalytic ring-opening polymerization, transesterification, and polymer end-group reaction studies; suitable for exploring metal-free catalytic systems
Strong organic base polymerization catalyst	5807-14-7	T161639	1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD)	≥98%	Used in ring-opening polymerization studies of cyclic esters and cyclic carbonates; can support PTMC molecular weight control and copolymerization system design
Monohydroxyl polymerization initiator	100-51-6	B108202	Benzyl alcohol	Anhydrous, ≥99.8%	Used for ring-opening polymerization initiation and end-group control; suitable for studies on PTMC molecular weight, chain-end structure, and model polymerization reactions
Dihydroxyl polymerization initiator	110-63-4	B1508458	1,4-Butanediol (BDO)	Anhydrous, ≥99%	Used to prepare hydroxyl-terminated PTMC, block copolymers, and polymer precursors that can be further crosslinked
Long-chain alcohol end-group regulator	112-53-8	D431501	1-Dodecanol	ACS, ≥98%	Used to regulate polymer chain-end hydrophobicity, chain length, and surface properties; related to studies on hydrophobic PTMC matrices and release behavior
Polyhydroxyl multi-arm polymerization initiator	115-77-5	P103696	Pentaerythritol (regulated as an explosive precursor)	AR, ≥98%	Used for the design of multi-arm PTMC, star-shaped polymers, and crosslinkable precursors; related to elastic networks and shape-stability studies

Table 2. Copolymer Modification Monomers and Reference Degradable Polymers

Detailed Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
L-lactic acid segment monomer	4511-42-6	S161079	L-(-)-Lactide	≥98%	Used to introduce polylactic acid segments and regulate the strength, crystallization behavior, and degradation period of PTMC copolymers
D-lactic acid segment monomer	13076-17-0	D190506	D-Lactide	≥99%	Used to regulate the stereochemical structure of polylactic acid segments and support performance studies of TMC-lactide copolymers
Racemic lactic acid segment monomer	95-96-5	S161100	DL-Lactide	≥98%	Used to prepare random polylactic acid segments and TMC-lactide copolymers; related to the regulation of rigid-flexible balance and degradation behavior
Glycolic acid segment monomer	502-97-6	G156824	Glycolide	≥98%	Used to introduce polyglycolic acid segments and regulate copolymer degradation rate, crystallization behavior, and mechanical strength
Flexible caprolactone segment monomer	502-44-3	C109521	ε-Caprolactone	≥99%	Used to introduce polycaprolactone segments and regulate the flexibility, crystallinity, and degradation period of PTMC-based copolymer materials
Absorbable p-dioxanone monomer	3041-16-5	D122246	1,4-Dioxan-2-one (p-dioxanone)	≥98%	Used in studies on absorbable polymers and copolymers; related to the design of sutures, scaffolds, and flexible degradable materials
Reference polymer for acidic degradation	26780-50-7	R486123	Resomer® RG 505, poly(D,L-lactide-co-glycolide) (PLGA)	Ester-terminated, Mw 54,000–69,000	Typical degradable polyester material used to compare PTMC surface erosion, non-acidic degradation, and drug release behavior
Reference flexible polyester material	24980-41-4	R432387	Resomer® C 209, polycaprolactone (PCL)	Ester-terminated	Flexible degradable polyester material used for comparison with PTMC in terms of flexibility, crystallinity, and degradation period
Reference rigid polyester material	26100-51-6	P169115	Polylactic acid	Mw ~60,000	Used to compare PTMC in terms of low-Tg flexibility, non-acidic degradation characteristics, and suitability for soft-tissue materials
Hydrophilic polyether release-modulating material	25322-68-3	P615493	Polyethylene oxide	Viscosity 65–115 cps	Used to improve material hydrophilicity, water penetration, and drug diffusion behavior; suitable for studies on sustained-release carriers and composite materials

Table 3. Products Related to End-Group Functionalization, Photocrosslinking, and Elastic Network Construction

Detailed Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Hydrophilic methacrylate functional monomer	868-77-9	H140643	2-Hydroxyethyl methacrylate (HEMA)	Anhydrous, ≥99%, contains 200 ppm MEHQ stabilizer, water ≤0.1%	Used in hydrophilic modification, photocrosslinked polymers, and hydrogel composite system studies; related to the regulation of PTMC surface hydrophilicity
Hydrophilic diacrylate crosslinker	26570-48-9	P109707	Poly(ethylene glycol) diacrylate (PEGDA)	Average molecular weight ~200, contains MEHQ stabilizer	Used to construct photocrosslinked networks and regulate material hydrophilicity, elastic structure, and swelling behavior
Reagent for introducing acryloyl end groups	814-68-6	A104614	Acryloyl chloride	≥96%, contains 200 ppm MEHQ stabilizer	Used to introduce acryloyl groups into hydroxyl-terminated polymers and prepare free-radical-crosslinkable PTMC derivatives
Reagent for introducing methacryloyl end groups	920-46-7	M109517	Methacryloyl chloride	≥95%, contains MEHQ stabilizer	Used for methacryloylation of polymer end groups and construction of photocurable PTMC precursors and elastic network materials
Methacrylation reagent for end-group modification	760-93-0	M102519	Methacrylic anhydride	≥94%, contains 0.2% Topanol CA as stabilizer	Used for end-group modification of hydroxyl-terminated PTMC to prepare crosslinkable macromonomers and photocurable materials
Photoinitiator for biomaterials	106797-53-9	H137984	2-Hydroxy-4′-(2-hydroxyethoxy)-2-methylpropiophenone	≥98% (HPLC)	Used for the preparation of photocrosslinked biomaterials, elastic networks, and hydrogel composite systems
UV free-radical initiator	24650-42-8	B105178	2,2-Dimethoxy-2-phenylacetophenone	≥99%	Used for free-radical photopolymerization and crosslinked network curing; supports studies on crosslinkable PTMC derivatives
Acylphosphine oxide photoinitiator	75980-60-8	T107643	Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO)	≥97%	Used in photocurable resins, crosslinked polymers, and three-dimensional forming material preparation; related to PTMC elastic network processing studies

Table 4. Products Related to Gel Carriers, Viscosity Regulation, and Degradation Evaluation

Detailed Category	CAS No.	Aladdin Cat. No.	Name	Specification or Purity	Product Features and Applications
Enzyme for PTMC enzymatic degradation evaluation	9001-62-1	L299011	Lipase PS from Burkholderia cepacia	Recombinant, EnzymoPure™, ≥23,000 U/g, pH 7.0, 50 °C, expressed in Burkholderia cepacia	Used to study PTMC enzymatic surface erosion, degradation rate, and degradation mechanism
High-molecular-weight gel carrier material	9067-32-7	S1519982	Sodium hyaluronate	≥99.8%, molecular weight: 1.7–2.6 million	Used in studies on absorbable gel carriers, soft-tissue filling systems, and PTMC microsphere dispersion systems
Natural polysaccharide gel matrix	9004-61-9	H131007	Hyaluronic acid	Moligand™, from rooster comb	Used in studies on soft-tissue materials, gel carriers, and biocompatible composite systems
Thickening and dispersing material for injectable systems	9004-32-4	C104986	Sodium carboxymethyl cellulose (CMC)	Viscosity: 1000–1400 mPa·s, USP grade	Used to regulate the viscosity of dispersion systems, improve microsphere suspension stability, and support sustained-release carrier preparation processes

Note: The products listed above are mainly intended for research, synthesis, formulation screening, or in vitro evaluation. Whether they can be used for medical devices, implantable materials, or biomedical-grade production should be determined according to the product COA, quality system, regulatory documents, and specific registration requirements. More product specifications, grades, and COA information can be searched on the Aladdin website using the product name, CAS number, or catalog number.

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