CN103163133B - Continuous filament reinforced plastic impregnation uniformity evaluation method - Google Patents

Abstract

A continuous filament reinforced plastic impregnation uniformity evaluation method includes a first step of taking an impregnation sample and cutting off a section of the sample, wherein sample cracking needs to be prevented in the cutting process, a second step of placing the sample on a plate grinding machine, carrying out wet grinding on the sample under flowing water through utilization of rough-thin waterproof abrasive paper in sequence, and placing the sample on a polishing machine to polish through utilization of polishing fabric and polishing paste until the section of the sample can be clearly seen under a microscope, a third step of placing the sample under the optical microscope for microscopic examination, a fourth step of taking pictures of the section of the sample, and a fifth step of carrying out statistical calculation and estimation. The continuous filament reinforced plastic impregnation uniformity evaluation method can enable continuous filament to be uniformly scattered and completely impregnated, and can also carry out qualitative evaluation on the continuous filament reinforced thermoplastic resin composite materials, and has the advantages of being simple and direct.

Description

The evaluation method of continuous fiber reinforced plastic dipping uniformity coefficient

Technical field

The present invention relates to the evaluation method of continuous fiber reinforced plastic dipping uniformity coefficient, be specifically related to carry out qualitative evaluation to the dipping effect of the continuous fiber prepreg tape of melt impregnation dipping preparation.

Background technology

It is the high-performance new material of progress of making a breakthrough in recent years that thermoplastic composite has, and has the distinguishing features such as high strength, high rigidity, dimensionally stable, low warpage, long service life, creep resistance be excellent.Because the melt viscosity of thermoplastic resin is generally all more than 100Pa.s, continuous fiber is caused to be difficult to obtain good dipping.Solve and how to obtain the key point that the goods with good dipping effect are this technology.

Chinese patent CN101474868B discloses a kind of Preparation equipment and the application thereof that relate to continuous fiber reinforced thermoplastic resin composite material presoaked belt.This complete equipment comprises creel, tension-adjusting gear, static eraser, preheating oven, two extrusion die, three roller immersion systems, cooling and shaping roller and traction collecting device, staggered two extrusion dies are adopted to carry out pre-preg to continuous fiber band, by the particular design of technique, all even dipping of fiber dispersion continuous fiber reinforced thermoplastic resin composite material presoaked belt completely can be obtained.Although adopt this technique can realize the melt impregnation of continuous fiber, its dipping degree of uniformity cannot quantitative evaluation, and its final effect reached can not be described.

Vetrotex company produces mixed fiber yarn can manufacture the good fiber-reinforced thermoplastic resin prepreg tape of dipping and pellet, namely first thermoplastic resin is carried out melt spinning, again with other fiber hybrid, then the method for heating and melting is adopted to prepare pellet, the apparent degree of impregnation of pellet prepared by the method is better, but does not provide the characterizing method of degree of impregnation in patent.

Summary of the invention

The object of the invention is to, provide continuous fiber reinforced plastic to flood the evaluation method of uniformity coefficient, to overcome the above-mentioned shortcoming and defect existing for prior art.Impregnation of fibers can be used for preparing fiber-reinforced thermoplastic resin composite material prepreg and pellet.The present invention is the technology can carrying out qualitative evaluation to continuous fiber reinforced thermoplastic resin composite material material strip and pellet.

In the present invention, continuous fiber reinforced plastic to be detected, referred to as sample, the shape of sample is bar shaped, and its cross sectional shape is circular.

The technical matters that will solve required for the present invention, can be achieved through the following technical solutions:

The evaluation method of continuous fiber reinforced plastic dipping uniformity coefficient, comprises the following steps:

(1) get dipping sample, and cut one section of sample and get off, in cutting process, will sample cracking be prevented;

Wherein, in step (1), sample is cylindrical structural, and the cross sectional shape of sample is circular, and the length cutting sample is 10mm.

(2) sample is carried out wet-milling on wafer lapping machine, then on buffing machine, use polishing fabric and antiscuffing paste polishing, until specimen cross section pattern is high-visible under the microscope;

Wherein, in step (2), if desired, adopt ultrasonic cleaning machine washed samples surface, remove residual antiscuffing paste.

(3) sample is placed in microscopy under optical microscope;

The sample prepared is placed on objective table under an optical microscope; Regulate microscopical enlargement factor, clearly can see specimen cross section, the fiber on cross section can be differentiated;

(4) cross-section photograph of sample is taken;

Wherein, in step (4), take pictures and adopt entirety to take pictures or gradation is taken pictures in cross section, and gradation adopts image synthesizing software to synthesize the overall photo in cross section after clapping; The photo of synthesis is adopted image processing software, distinguishes pars fibrosa and resin portion.(5) statistical computation is carried out to the pars fibrosa in the cross section of sample and resin portion, evaluates:

A, the cross section of sample is divided into concentric circles or the circle ring area of a plurality of homalographic: the firstth district, the secondth district, the 3rd district, the n-thth district;

B, calculate respectively, the ratio of pars fibrosa and the subregion total area in each subregion, is designated as: Fn.Fn is the ratio of pars fibrosa and the subregion total area, and n is 1,2,3 display place subregions;

Hundred times of standard deviations of C, ratio calculated:

$\mathrm{Dx}=100\sqrt{\frac{{\mathrm{\Σ}}_{n=1}^N{(F_n-\stackrel{\‾}{F})}^2}{N-1}}$

Wherein, Dx is standard deviation;

Fn is the ratio of pars fibrosa area and this subregion total area in the n-th subregion;

for the average of Fn;

X is the sequence number of sample to be tested.

Standard deviation represents each data and average difference size, i.e. the fluctuation size of a batch data in one group of data.Hundred times of standard deviations of ratio are larger, and the extremely uneven of the distribution of fiber in regional is described, namely D value is larger, and illustrate that to flood uniformity coefficient poorer, D value is less, illustrate that to flood uniformity coefficient better.

Wherein, in step (5), described pars fibrosa by glass fibre, carbon fiber, aramid fiber any one form.

Wherein, in step (5), described resin portion by tygon, polypropylene, polyphenylene sulfide, polyetheretherketone any one form.

Beneficial effect of the present invention:

The present invention is that one can make continuous fiber be uniformly dispersed, and dipping completely, and can carry out the technology of qualitative evaluation to continuous fiber reinforced thermoplastic resin composite material.

The present invention effectively avoids infiltration and spreads this complicated dynamic process, and only calculate impregnation result, computing method are more direct.

Accompanying drawing explanation

Fig. 1 a kind ofly floods the pars fibrosa of specimen cross section and the distribution plan of resin portion.

Fig. 2 is the another kind of dipping pars fibrosa of specimen cross section and the distribution plan of resin portion.

Fig. 3 is the third dipping pars fibrosa of specimen cross section and distribution plan of resin portion.

Reference numeral:

First district 2 of district 1, second, the 3rd district 3.

Embodiment

Below in conjunction with specific embodiment, progressive explanation is done to the present invention.Should be understood that following examples only for illustration of the present invention but not for limiting scope of the present invention.

Embodiment 1

The evaluation method of continuous fiber reinforced plastic dipping uniformity coefficient, comprises the following steps:

(1) get dipping sample, and cut one section of sample and get off, in cutting process, will sample cracking be prevented; Sample is cylindrical structural, and the cross sectional shape of sample is circular, and the length cutting sample is 10mm.

(2) by sample on wafer lapping machine successively with silicon carbide paper from coarse to fine wet-milling under circulating water, then on buffing machine with polishing fabric and antiscuffing paste polishing, until specimen cross section pattern is high-visible under the microscope;

Sand paper is respectively 300#, 500#, 800#.

If desired, adopt ultrasonic cleaning machine washed samples surface, remove residual antiscuffing paste.

(3) sample is placed in microscopy under optical microscope;

The sample prepared is placed on objective table under an optical microscope; Regulate microscopical enlargement factor, clearly can see specimen cross section, the fiber on cross section can be differentiated;

(4) cross-section photograph of sample is taken;

If once can not photograph comprehensively, several times, the overall photo in image synthesizing software synthesis cross section can be adopted afterwards; The photo of synthesis is adopted the image processing software process such as photoshop, due under polarizing microscope, the color of resin and fiber is visibly different, resin is White-opalescent, fiber is black (carbon fiber), or transparent (glass fibre), utilize aberration to distinguish and obtain fiber and resin constituency respectively;

(5) statistical computation is carried out to the pars fibrosa in the cross section of sample and resin portion, make evaluation.

Pars fibrosa by glass fibre, carbon fiber, aramid fiber any one form.

Resin portion by tygon, polypropylene, polyphenylene sulfide, polyetheretherketone any one form.

The evaluation of continuous fiber reinforced plastic dipping uniformity coefficient:

Fig. 1 a kind ofly floods the pars fibrosa of specimen cross section and the distribution plan of resin portion.Fig. 2 is the another kind of dipping pars fibrosa of specimen cross section and the distribution plan of resin portion.

Fig. 1 with Fig. 2 is under identical fiber volume fraction, the fiber distribution situation in the cross section of continuous fiber dipping sample.

In the present embodiment, N value is 3 to be described, but not as limit.

(1) cross section is divided into concentric circles (annulus) region of three homalographics: the first district 2 of district 1, second, the 3rd district 3.Calculate the ratio of pars fibrosa and the subregion total area in each subregion respectively, be designated as: F ₁, F ₂, F ₃.

(2) data analysis of Fig. 1, in table 1:

Table 1 is the ratio (the subregion total area: 14470 pixels) of fiber and the subregion total area in each subregion of Fig. 1

Area code	Pixel	Ratio
			1	10409	0.2806
2	12574	0.1310
			3	13828	0.0444

Hundred times of standard deviations of ratio calculated:

D ₁=100D（n）＝0.1195×100＝11.95

(3) data analysis of Fig. 2, in table 2:

Table 2 is the ratio (the subregion total area: 14470 pixels) of fiber and the subregion total area in each subregion of Fig. 2

Area code	Pixel	Ratio
			1	9599	0.3366
2	13132	0.0925
			3	14079	0.0270

Hundred times of standard deviations of ratio calculated:

D ₂=100D（n）＝0.1632×100＝16.32

(4) data analysis of Fig. 3, in table 3:

Table 3 is the ratio (the subregion total area: 14470 pixels) of fiber and the subregion total area in each subregion of Fig. 3

Area code	Pixel	Ratio
			1	11773	0.1863
2	11905	0.1772
			3	12041	0.1679

Hundred times of standard deviations of ratio calculated:

D ₃=100D（n）＝0.009261×100＝0.9261

Standard deviation represents each data and average difference size, i.e. the fluctuation size of a batch data in one group of data.Hundred times of standard deviations of ratio are larger, and the extremely uneven of the distribution of fiber in regional is described, namely D value is larger, and illustrate that to flood uniformity coefficient poorer, D value is less, illustrate that to flood uniformity coefficient better.When it is generally acknowledged that D value is less than 5, good disperse state and degree of impregnation can be reached.

According to the above analysis, D ₃<D ₁<D ₂, that is, in identical fiber volume fraction, the dispersion effect in Fig. 1 is more effective than the mark in Fig. 2, and the dispersion effect in Fig. 3 is more effective than the mark in Fig. 1.

Assay is carried out to prepared product, process conditions optimum under determining best disperse state.

Be illustrated the specific embodiment of the present invention above, but the present invention is not as limit, only otherwise depart from aim of the present invention, the present invention can also have various change.

Claims (6)

1. the evaluation method of continuous fiber reinforced plastic dipping uniformity coefficient, is characterized in that, comprise the following steps:

Step 1: get dipping sample, and cut one section of sample;

Step 2: sample is carried out wet-milling and polishing, until specimen cross section pattern is high-visible under the microscope; Described being finished to carries out polishing with polishing fabric and antiscuffing paste on buffing machine;

Step 3: sample is placed in microscopy under optical microscope;

Step 4: the cross-section photograph of shooting sample;

Step 5: statistical computation is carried out to the pars fibrosa in the cross section of sample and resin portion, evaluates;

Step 5.1: the concentric circles or the circle ring segments that the cross section of sample are divided into N number of homalographic;

Step 5.2: for each subregion, calculates the ratio F of pars fibrosa area and this subregion total area in this subregion _n, n is subregion sequence number;

Step 5.3: hundred times of standard deviations of ratio calculated:

$D_X=100\sqrt{\frac{{\mathrm{\&Sigma;}}_{n=1}^N{(F_n-\stackrel{\&OverBar;}{F})}^2}{N-1}};$

Wherein, D _xfor standard deviation;

F _nbe the ratio of pars fibrosa area and this subregion total area in the n-th subregion;

for the average of Fn;

X is the sequence number of sample to be tested;

Step 5.4: the fiber dispersion uniformity coefficient evaluating this subregion with hundred times of standard deviation sizes.

2. method according to claim 1, is characterized in that: in step 1, and described sample is cylindrical structural, and described specimen cross section shape is circular.

3. method according to claim 1, is characterized in that: in step 2, adopts ultrasonic cleaning machine washed samples surface further, removes residual antiscuffing paste.

4. method according to claim 1, is characterized in that: in step 4, and described cross-section photograph is adopt overall taking pictures or the overall photo of synthesis after gradation is taken pictures, gradation is taken pictures.

5. method according to claim 1, is characterized in that: in step 5, described pars fibrosa by glass fibre, carbon fiber, aramid fiber any one form.

6. method according to claim 1, is characterized in that: in step 5, described resin portion by tygon, polypropylene, polyphenylene sulfide, polyetheretherketone any one form.