**2. Summary of biomedical polymer materials**

Biomedical polymer material is an important component of biological material and is a remarkable functional polymer. It involves in physics, chemistry, biochemistry, medicine, pathology subjects. The synthetic polymer materials and the organisms (natural polymer) have a very similar chemical structure, which determines their similarity in performance and enables high molecular polymer to meet the many complicate and rigorous functional requirements for medical products. Most metal and inorganic materials are incapable in this respect. Presently, high molecular polymers are widely used in medical products.

#### **2.1 Presently there are two types of high molecular polymers: Non-biodegradable and biodegradable polymer materials**

Non-biodegradable biomedical polymer material is widely used in manufacturing of adhesives, coating, and artificial lens as well as for repair of the many soft and hard tissues and organs of human body such as ligament, tendon, skin, blood vessel, artificial organs, bone and teeth. Most non-biodegradable biomedical polymer materials have no biological activity and are difficult to bond firmly with tissues and thus may result in toxicity and allergic reaction. Biodegradable biomedical polymer material is mainly used in temporary execution and replacement of tissue and organ functions in clinic or be used as the medicine controlled-release system and delivery carrier, absorbable surgical suture and wound dressings. It is readily biodegradable and the degradation products can be excreted through metabolism. Thus, it has no negative effect to tissue growth. Presently, it has become the key focus in development of biomedical polymer materials.


Table 1. Category of Biomedical Polymers

However, biomedical polymer is an interdisciplinary subject and has varying types of classification based on different purposes and practices. For example, it can be categorized based on the source and application purpose of the medical polymer or based on the influence of living tissues to the materials. Presently there is no uniform standard for the classification.

#### **2.2 Biomedical polymer material**

Polymer material is generally composed of high polymers and low molecular weight substances. High polymers are divided into homopolymer, copolymer, blends and oligomer; Low molecular weight materials include: 1) additives: regulator, chain transfer agent,

Biomedical polymer material is an important component of biological material and is a remarkable functional polymer. It involves in physics, chemistry, biochemistry, medicine, pathology subjects. The synthetic polymer materials and the organisms (natural polymer) have a very similar chemical structure, which determines their similarity in performance and enables high molecular polymer to meet the many complicate and rigorous functional requirements for medical products. Most metal and inorganic materials are incapable in this

**2.1 Presently there are two types of high molecular polymers: Non-biodegradable and** 

Non-biodegradable biomedical polymer material is widely used in manufacturing of adhesives, coating, and artificial lens as well as for repair of the many soft and hard tissues and organs of human body such as ligament, tendon, skin, blood vessel, artificial organs, bone and teeth. Most non-biodegradable biomedical polymer materials have no biological activity and are difficult to bond firmly with tissues and thus may result in toxicity and allergic reaction. Biodegradable biomedical polymer material is mainly used in temporary execution and replacement of tissue and organ functions in clinic or be used as the medicine controlled-release system and delivery carrier, absorbable surgical suture and wound dressings. It is readily biodegradable and the degradation products can be excreted through metabolism. Thus, it has no negative effect to tissue growth. Presently, it has become the key

respect. Presently, high molecular polymers are widely used in medical products.

Non-biodegradable Polymer Materials Biodegradable Polymer Material

Polyethylene Modified natural polysaccharides

Polytetrafluoroethene -PTFE, etc. (Back spinning) synthetic polyester Dacron Polypeptide-polyolefine, silk ossein

However, biomedical polymer is an interdisciplinary subject and has varying types of classification based on different purposes and practices. For example, it can be categorized based on the source and application purpose of the medical polymer or based on the influence of living tissues to the materials. Presently there is no uniform standard for the

Polymer material is generally composed of high polymers and low molecular weight substances. High polymers are divided into homopolymer, copolymer, blends and oligomer; Low molecular weight materials include: 1) additives: regulator, chain transfer agent,

**2. Summary of biomedical polymer materials** 

focus in development of biomedical polymer materials.

Polyacrylate Protein

Carbon-graphite fiber, etc. PLA

Table 1. Category of Biomedical Polymers

**2.2 Biomedical polymer material** 

classification.

Silicone Rubber Polyvinyl alcohol

**biodegradable polymer materials** 

terminator and emulsifier; 2) additives: plasticizers, stabilizer, filler and colorant etc.; 3) unreacted monomer, residual catalyst, etc.

Compared with ordinary organic substance, polymer-a long chain connected by multiple monomer units through covalent bonds—features diversified and designable structure, with very high mechanical strength and non-fixed molecular weight. Polymer is partially crystallized or non-crystallized and provides the properties of elastomer and fluid.

Table 2. Polymer materials

### **2.3 Basic requirements of biomedical polymer and common materials**

Biomedical polymer is directly applied to human body and is closely related to human health. Therefore, the materials used for clinic should be strictly controlled, otherwise, it may cause adverse effect instead of life saving. Below are requirements on properties and performances of the biomedical polymer:


Requirements on body effect of biomedical polymer

Application of Infrared Spectroscopy in Biomedical Polymer Materials 169

from the small molecular organism that belongs to polymer-based bands. Conformation

Adding modifier into certain materials may obtain new material with different

Development of new materials, assimilation of introduced technology and gradual

Infrared spectroscopy is the most effective method to identify the various polymers and additives in polymer material analysis. The main advantages of the infrared spectroscopy include: 1) it does not cause damage to the sample under analysis; 2) it may analyze organic and inorganic compounds of various physical states (gas, liquid and solid) and various exterior forms (elastic, fibrous, thin film, coating and power form); 3) well-developed molecular vibration spectroscopy (the basis of IR spectrum) makes it easy to understand the explanation of the IR spectrum of the compound; 4) a large number of standard infrared spectrogram for various kinds of chemical compounds have already been published in the world and can be referred to in spectra analysis. With application of computer and establishment and improvement of spectral database, the spectral identification will be easier and conclusion will be more reliable. Chemical compounds of different chemical structures have infrared absorption spectroscopy of different characteristics, There is no completely identical spectroscopy except for some isomers. Moreover, each absorption band (band) in the infrared spectrogram represents a certain vibration type of a certain atomic group or radical in the chemical compound. Their vibration frequency (corresponding to the wave numbers of the absorption band on the spectrum) is directly related to the mass and chemical bond strength of the atom in the atomic group or radical. They are consequently subject to changes of proximity structure and different influences of chemical environment. As each molecule of the polymer contains a great number of atoms, it may be considered that the polymer spectrum would be extremely complicate with considerable number of normal vibration. But this is not the case, IR spectra of some polymers are more simple than that of the monomers. This is because polymer chain is made of many repetitive units and each repetitive unit has basically same bond force constant with roughly similar vibration frequency. Moreover, due to limitation of strict selection law, only part of the vibration has

bands; Stereoregularity bands; Conformational regularity band; Crystal band

Such bands are of great significance to the study of polymer.

5. Determination of the sequence distribution of the copolymer

performances. But the difference of the infrared spectra maybe small.

internationalization; discrimination of true and false materials

2. Determination of chemical composition 3. Determination of degree of branching 4. Determination of copolymer composition

6. Influence from additives

**2.4.2 Change of polymer materials** 

**2.4.3 Analyses on polymer material** 

Monomer—polymer—Products—Application

**3. Characteristics of polymer IR spectrum** 


Requirements for biomedical polymer production and processing: besides the strict control on biomedical polymer itself, matters harmful to human body shall also be prevented during material production; the purity of the raw materials used in biomedical polymer synthesis shall be strictly controlled, no harmful matter is allowed and the content of heavy mental shall be within the limit; additive processing shall meet medical standard; the production environment should meet proper standard for cleanliness.

The commonly used biomedical polymer materials include Polytetrafluoroethene, polyurethane, polyvinyl chloride, silicone rubber, polypropylene, polysiloxane gel, poly methyl acrylate, chitin derivatives and Polymethylmethacrylate.

#### **2.4 Biomedical polymer material study content**

Structure-property relationship: different materials have different properties; the same kinds of materials have different properties; the property of the material not only relevant to its composition but more importantly is relevant to its structure. Moreover, its basic performance and processing performance are sometimes inconsistent with its operational performances.

Table 3. Structure-property relationship of Polymer Material

#### **2.4.1 Polymer chain structure study**

1. Polymer-based band

Most bands in the spectra are characterized by small molecule band with structure similar to repetitive units, i.e. elemental bands; also there are some unique absorbing bands different from the small molecular organism that belongs to polymer-based bands. Conformation bands; Stereoregularity bands; Conformational regularity band; Crystal band

Such bands are of great significance to the study of polymer.


168 Macro to Nano Spectroscopy

The commonly used biomedical polymer materials include Polytetrafluoroethene, polyurethane, polyvinyl chloride, silicone rubber, polypropylene, polysiloxane gel, poly

Structure-property relationship: different materials have different properties; the same kinds of materials have different properties; the property of the material not only relevant to its composition but more importantly is relevant to its structure. Moreover, its basic performance and processing performance are sometimes inconsistent with its operational

> Polymer molecular structure

Basic properties

Product properties

Polymer Process Product

Processing properties

Polymer aggregation structure

In-service evaluation (Subjective standard)

Most bands in the spectra are characterized by small molecule band with structure similar to repetitive units, i.e. elemental bands; also there are some unique absorbing bands different

5. Does not cause allergic reaction or interfere with the body's immune mechanism 6. Does not damage adjacent tissue or cause calcified deposition on material surface. 7. Excellent blood compatibility without causing coagulation when contacting with blood. Requirements for biomedical polymer production and processing: besides the strict control on biomedical polymer itself, matters harmful to human body shall also be prevented during material production; the purity of the raw materials used in biomedical polymer synthesis shall be strictly controlled, no harmful matter is allowed and the content of heavy mental shall be within the limit; additive processing shall meet medical standard; the

production environment should meet proper standard for cleanliness.

methyl acrylate, chitin derivatives and Polymethylmethacrylate.

Table 3. Structure-property relationship of Polymer Material

**2.4.1 Polymer chain structure study** 

1. Polymer-based band

Instrument measuring result (Objective standard)

**2.4 Biomedical polymer material study content** 

1. Non-toxic, i.e. chemically inert

2. No pyrogenic reaction 3. Non carcinogenic 4. Non-teratogenic

performances.

Adding modifier into certain materials may obtain new material with different performances. But the difference of the infrared spectra maybe small.

#### **2.4.2 Change of polymer materials**

Monomer—polymer—Products—Application

#### **2.4.3 Analyses on polymer material**

Development of new materials, assimilation of introduced technology and gradual internationalization; discrimination of true and false materials
